diff --git a/.gitignore b/.gitignore
index 0bf694c..2f33739 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,5 @@
 .DS_Store
 *.[568ao]
-*.pb.go
 *.ao
 *.so
 *.pyc
@@ -13,5 +12,4 @@
 _obj
 _test
 _testmain.go
-compiler/protoc-gen-go
-compiler/testdata/extension_test
+protoc-gen-go/testdata/multi/*.pb.go
diff --git a/types/any/any.pb.go b/types/any/any.pb.go
new file mode 100644
index 0000000..b93383f
--- /dev/null
+++ b/types/any/any.pb.go
@@ -0,0 +1,110 @@
+// Code generated by protoc-gen-go.
+// source: github.com/golang/protobuf/types/any/any.proto
+// DO NOT EDIT!
+
+/*
+Package any is a generated protocol buffer package.
+
+It is generated from these files:
+	github.com/golang/protobuf/types/any/any.proto
+
+It has these top-level messages:
+	Any
+*/
+package any
+
+import proto "github.com/golang/protobuf/proto"
+import fmt "fmt"
+import math "math"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+const _ = proto.ProtoPackageIsVersion1
+
+// `Any` contains an arbitrary serialized message along with a URL
+// that describes the type of the serialized message.
+//
+//
+// JSON
+// ====
+// The JSON representation of an `Any` value uses the regular
+// representation of the deserialized, embedded message, with an
+// additional field `@type` which contains the type URL. Example:
+//
+//     package google.profile;
+//     message Person {
+//       string first_name = 1;
+//       string last_name = 2;
+//     }
+//
+//     {
+//       "@type": "type.googleapis.com/google.profile.Person",
+//       "firstName": <string>,
+//       "lastName": <string>
+//     }
+//
+// If the embedded message type is well-known and has a custom JSON
+// representation, that representation will be embedded adding a field
+// `value` which holds the custom JSON in addition to the `@type`
+// field. Example (for message [google.protobuf.Duration][]):
+//
+//     {
+//       "@type": "type.googleapis.com/google.protobuf.Duration",
+//       "value": "1.212s"
+//     }
+//
+type Any struct {
+	// A URL/resource name whose content describes the type of the
+	// serialized message.
+	//
+	// For URLs which use the schema `http`, `https`, or no schema, the
+	// following restrictions and interpretations apply:
+	//
+	// * If no schema is provided, `https` is assumed.
+	// * The last segment of the URL's path must represent the fully
+	//   qualified name of the type (as in `path/google.protobuf.Duration`).
+	// * An HTTP GET on the URL must yield a [google.protobuf.Type][]
+	//   value in binary format, or produce an error.
+	// * Applications are allowed to cache lookup results based on the
+	//   URL, or have them precompiled into a binary to avoid any
+	//   lookup. Therefore, binary compatibility needs to be preserved
+	//   on changes to types. (Use versioned type names to manage
+	//   breaking changes.)
+	//
+	// Schemas other than `http`, `https` (or the empty schema) might be
+	// used with implementation specific semantics.
+	//
+	TypeUrl string `protobuf:"bytes,1,opt,name=type_url,json=typeUrl" json:"type_url,omitempty"`
+	// Must be valid serialized data of the above specified type.
+	Value []byte `protobuf:"bytes,2,opt,name=value,proto3" json:"value,omitempty"`
+}
+
+func (m *Any) Reset()                    { *m = Any{} }
+func (m *Any) String() string            { return proto.CompactTextString(m) }
+func (*Any) ProtoMessage()               {}
+func (*Any) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
+
+func init() {
+	proto.RegisterType((*Any)(nil), "google.protobuf.Any")
+}
+
+var fileDescriptor0 = []byte{
+	// 183 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xe2, 0xd2, 0x4b, 0xcf, 0x2c, 0xc9,
+	0x28, 0x4d, 0xd2, 0x4b, 0xce, 0xcf, 0xd5, 0x4f, 0xcf, 0xcf, 0x49, 0xcc, 0x4b, 0xd7, 0x2f, 0x28,
+	0xca, 0x2f, 0xc9, 0x4f, 0x2a, 0x4d, 0xd3, 0x2f, 0xa9, 0x2c, 0x48, 0x2d, 0xd6, 0x4f, 0xcc, 0xab,
+	0x04, 0x61, 0x3d, 0xb0, 0xb0, 0x10, 0x7f, 0x7a, 0x7e, 0x7e, 0x7a, 0x4e, 0xaa, 0x1e, 0x4c, 0x91,
+	0x92, 0x19, 0x17, 0xb3, 0x63, 0x5e, 0xa5, 0x90, 0x24, 0x17, 0x07, 0x48, 0x79, 0x7c, 0x69, 0x51,
+	0x8e, 0x04, 0xa3, 0x02, 0xa3, 0x06, 0x67, 0x10, 0x3b, 0x88, 0x1f, 0x5a, 0x94, 0x23, 0x24, 0xc2,
+	0xc5, 0x5a, 0x96, 0x98, 0x53, 0x9a, 0x2a, 0xc1, 0x04, 0x14, 0xe7, 0x09, 0x82, 0x70, 0x9c, 0x02,
+	0xb8, 0x84, 0x81, 0x76, 0xea, 0xa1, 0x19, 0xe7, 0xc4, 0x01, 0x34, 0x2c, 0x00, 0xc4, 0x09, 0x60,
+	0x8c, 0x62, 0x06, 0x5a, 0xbb, 0x80, 0x91, 0x71, 0x11, 0x13, 0xb3, 0x7b, 0x80, 0xd3, 0x2a, 0x26,
+	0x39, 0x77, 0x88, 0xda, 0x00, 0xa8, 0x5a, 0xbd, 0xf0, 0xd4, 0x9c, 0x1c, 0xef, 0xbc, 0xfc, 0xf2,
+	0xbc, 0x10, 0x90, 0x43, 0x93, 0xd8, 0xc0, 0x86, 0x18, 0x03, 0x02, 0x00, 0x00, 0xff, 0xff, 0x69,
+	0x04, 0x7f, 0x3b, 0xd3, 0x00, 0x00, 0x00,
+}
diff --git a/types/any/any.proto b/types/any/any.proto
new file mode 100644
index 0000000..7689d50
--- /dev/null
+++ b/types/any/any.proto
@@ -0,0 +1,100 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package google.protobuf;
+option go_package = "any";
+
+option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option java_package = "com.google.protobuf";
+option java_outer_classname = "AnyProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
+option objc_class_prefix = "GPB";
+
+// `Any` contains an arbitrary serialized message along with a URL
+// that describes the type of the serialized message.
+//
+//
+// JSON
+// ====
+// The JSON representation of an `Any` value uses the regular
+// representation of the deserialized, embedded message, with an
+// additional field `@type` which contains the type URL. Example:
+//
+//     package google.profile;
+//     message Person {
+//       string first_name = 1;
+//       string last_name = 2;
+//     }
+//
+//     {
+//       "@type": "type.googleapis.com/google.profile.Person",
+//       "firstName": <string>,
+//       "lastName": <string>
+//     }
+//
+// If the embedded message type is well-known and has a custom JSON
+// representation, that representation will be embedded adding a field
+// `value` which holds the custom JSON in addition to the `@type`
+// field. Example (for message [google.protobuf.Duration][]):
+//
+//     {
+//       "@type": "type.googleapis.com/google.protobuf.Duration",
+//       "value": "1.212s"
+//     }
+//
+message Any {
+  // A URL/resource name whose content describes the type of the
+  // serialized message.
+  //
+  // For URLs which use the schema `http`, `https`, or no schema, the
+  // following restrictions and interpretations apply:
+  //
+  // * If no schema is provided, `https` is assumed.
+  // * The last segment of the URL's path must represent the fully
+  //   qualified name of the type (as in `path/google.protobuf.Duration`).
+  // * An HTTP GET on the URL must yield a [google.protobuf.Type][]
+  //   value in binary format, or produce an error.
+  // * Applications are allowed to cache lookup results based on the
+  //   URL, or have them precompiled into a binary to avoid any
+  //   lookup. Therefore, binary compatibility needs to be preserved
+  //   on changes to types. (Use versioned type names to manage
+  //   breaking changes.)
+  //
+  // Schemas other than `http`, `https` (or the empty schema) might be
+  // used with implementation specific semantics.
+  //
+  string type_url = 1;
+
+  // Must be valid serialized data of the above specified type.
+  bytes value = 2;
+}
diff --git a/types/doc.go b/types/doc.go
new file mode 100644
index 0000000..efc1d47
--- /dev/null
+++ b/types/doc.go
@@ -0,0 +1,6 @@
+/*
+Package types will contain code for interacting with well-known types.
+
+For now, it is a placeholder; see its subdirectories for the protos themselves.
+*/
+package types
diff --git a/types/duration/duration.pb.go b/types/duration/duration.pb.go
new file mode 100644
index 0000000..3ac552e
--- /dev/null
+++ b/types/duration/duration.pb.go
@@ -0,0 +1,106 @@
+// Code generated by protoc-gen-go.
+// source: github.com/golang/protobuf/types/duration/duration.proto
+// DO NOT EDIT!
+
+/*
+Package duration is a generated protocol buffer package.
+
+It is generated from these files:
+	github.com/golang/protobuf/types/duration/duration.proto
+
+It has these top-level messages:
+	Duration
+*/
+package duration
+
+import proto "github.com/golang/protobuf/proto"
+import fmt "fmt"
+import math "math"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+const _ = proto.ProtoPackageIsVersion1
+
+// A Duration represents a signed, fixed-length span of time represented
+// as a count of seconds and fractions of seconds at nanosecond
+// resolution. It is independent of any calendar and concepts like "day"
+// or "month". It is related to Timestamp in that the difference between
+// two Timestamp values is a Duration and it can be added or subtracted
+// from a Timestamp. Range is approximately +-10,000 years.
+//
+// Example 1: Compute Duration from two Timestamps in pseudo code.
+//
+//     Timestamp start = ...;
+//     Timestamp end = ...;
+//     Duration duration = ...;
+//
+//     duration.seconds = end.seconds - start.seconds;
+//     duration.nanos = end.nanos - start.nanos;
+//
+//     if (duration.seconds < 0 && duration.nanos > 0) {
+//       duration.seconds += 1;
+//       duration.nanos -= 1000000000;
+//     } else if (durations.seconds > 0 && duration.nanos < 0) {
+//       duration.seconds -= 1;
+//       duration.nanos += 1000000000;
+//     }
+//
+// Example 2: Compute Timestamp from Timestamp + Duration in pseudo code.
+//
+//     Timestamp start = ...;
+//     Duration duration = ...;
+//     Timestamp end = ...;
+//
+//     end.seconds = start.seconds + duration.seconds;
+//     end.nanos = start.nanos + duration.nanos;
+//
+//     if (end.nanos < 0) {
+//       end.seconds -= 1;
+//       end.nanos += 1000000000;
+//     } else if (end.nanos >= 1000000000) {
+//       end.seconds += 1;
+//       end.nanos -= 1000000000;
+//     }
+//
+type Duration struct {
+	// Signed seconds of the span of time. Must be from -315,576,000,000
+	// to +315,576,000,000 inclusive.
+	Seconds int64 `protobuf:"varint,1,opt,name=seconds" json:"seconds,omitempty"`
+	// Signed fractions of a second at nanosecond resolution of the span
+	// of time. Durations less than one second are represented with a 0
+	// `seconds` field and a positive or negative `nanos` field. For durations
+	// of one second or more, a non-zero value for the `nanos` field must be
+	// of the same sign as the `seconds` field. Must be from -999,999,999
+	// to +999,999,999 inclusive.
+	Nanos int32 `protobuf:"varint,2,opt,name=nanos" json:"nanos,omitempty"`
+}
+
+func (m *Duration) Reset()                    { *m = Duration{} }
+func (m *Duration) String() string            { return proto.CompactTextString(m) }
+func (*Duration) ProtoMessage()               {}
+func (*Duration) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
+
+func init() {
+	proto.RegisterType((*Duration)(nil), "google.protobuf.Duration")
+}
+
+var fileDescriptor0 = []byte{
+	// 186 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xe2, 0xb2, 0x48, 0xcf, 0x2c, 0xc9,
+	0x28, 0x4d, 0xd2, 0x4b, 0xce, 0xcf, 0xd5, 0x4f, 0xcf, 0xcf, 0x49, 0xcc, 0x4b, 0xd7, 0x2f, 0x28,
+	0xca, 0x2f, 0xc9, 0x4f, 0x2a, 0x4d, 0xd3, 0x2f, 0xa9, 0x2c, 0x48, 0x2d, 0xd6, 0x4f, 0x29, 0x2d,
+	0x4a, 0x2c, 0xc9, 0xcc, 0xcf, 0x83, 0x33, 0xf4, 0xc0, 0x0a, 0x84, 0xf8, 0xd3, 0xf3, 0xf3, 0xd3,
+	0x73, 0x52, 0xf5, 0x60, 0xca, 0x95, 0xac, 0xb8, 0x38, 0x5c, 0xa0, 0x4a, 0x84, 0x24, 0xb8, 0xd8,
+	0x8b, 0x53, 0x93, 0xf3, 0xf3, 0x52, 0x8a, 0x25, 0x18, 0x15, 0x18, 0x35, 0x98, 0x83, 0x60, 0x5c,
+	0x21, 0x11, 0x2e, 0xd6, 0xbc, 0xc4, 0xbc, 0xfc, 0x62, 0x09, 0x26, 0xa0, 0x38, 0x6b, 0x10, 0x84,
+	0xe3, 0x14, 0xc5, 0x25, 0x0c, 0x74, 0x81, 0x1e, 0x9a, 0x91, 0x4e, 0xbc, 0x30, 0x03, 0x03, 0x40,
+	0x22, 0x01, 0x8c, 0x51, 0x1c, 0x30, 0x47, 0x2c, 0x60, 0x64, 0x5c, 0xc4, 0xc4, 0xec, 0x1e, 0xe0,
+	0xb4, 0x8a, 0x49, 0xce, 0x1d, 0xa2, 0x2b, 0x00, 0xaa, 0x4b, 0x2f, 0x3c, 0x35, 0x27, 0xc7, 0x3b,
+	0x2f, 0xbf, 0x3c, 0x2f, 0x04, 0xe4, 0x81, 0x24, 0x36, 0xb0, 0x71, 0xc6, 0x80, 0x00, 0x00, 0x00,
+	0xff, 0xff, 0x04, 0x47, 0x33, 0x15, 0xeb, 0x00, 0x00, 0x00,
+}
diff --git a/types/duration/duration.proto b/types/duration/duration.proto
new file mode 100644
index 0000000..d2fbc88
--- /dev/null
+++ b/types/duration/duration.proto
@@ -0,0 +1,97 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package google.protobuf;
+option go_package = "duration";
+
+option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option java_package = "com.google.protobuf";
+option java_outer_classname = "DurationProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
+option objc_class_prefix = "GPB";
+
+// A Duration represents a signed, fixed-length span of time represented
+// as a count of seconds and fractions of seconds at nanosecond
+// resolution. It is independent of any calendar and concepts like "day"
+// or "month". It is related to Timestamp in that the difference between
+// two Timestamp values is a Duration and it can be added or subtracted
+// from a Timestamp. Range is approximately +-10,000 years.
+//
+// Example 1: Compute Duration from two Timestamps in pseudo code.
+//
+//     Timestamp start = ...;
+//     Timestamp end = ...;
+//     Duration duration = ...;
+//
+//     duration.seconds = end.seconds - start.seconds;
+//     duration.nanos = end.nanos - start.nanos;
+//
+//     if (duration.seconds < 0 && duration.nanos > 0) {
+//       duration.seconds += 1;
+//       duration.nanos -= 1000000000;
+//     } else if (durations.seconds > 0 && duration.nanos < 0) {
+//       duration.seconds -= 1;
+//       duration.nanos += 1000000000;
+//     }
+//
+// Example 2: Compute Timestamp from Timestamp + Duration in pseudo code.
+//
+//     Timestamp start = ...;
+//     Duration duration = ...;
+//     Timestamp end = ...;
+//
+//     end.seconds = start.seconds + duration.seconds;
+//     end.nanos = start.nanos + duration.nanos;
+//
+//     if (end.nanos < 0) {
+//       end.seconds -= 1;
+//       end.nanos += 1000000000;
+//     } else if (end.nanos >= 1000000000) {
+//       end.seconds += 1;
+//       end.nanos -= 1000000000;
+//     }
+//
+message Duration {
+
+  // Signed seconds of the span of time. Must be from -315,576,000,000
+  // to +315,576,000,000 inclusive.
+  int64 seconds = 1;
+
+  // Signed fractions of a second at nanosecond resolution of the span
+  // of time. Durations less than one second are represented with a 0
+  // `seconds` field and a positive or negative `nanos` field. For durations
+  // of one second or more, a non-zero value for the `nanos` field must be
+  // of the same sign as the `seconds` field. Must be from -999,999,999
+  // to +999,999,999 inclusive.
+  int32 nanos = 2;
+}
diff --git a/types/empty/empty.pb.go b/types/empty/empty.pb.go
new file mode 100644
index 0000000..ab3f972
--- /dev/null
+++ b/types/empty/empty.pb.go
@@ -0,0 +1,62 @@
+// Code generated by protoc-gen-go.
+// source: github.com/golang/protobuf/types/empty/empty.proto
+// DO NOT EDIT!
+
+/*
+Package empty is a generated protocol buffer package.
+
+It is generated from these files:
+	github.com/golang/protobuf/types/empty/empty.proto
+
+It has these top-level messages:
+	Empty
+*/
+package empty
+
+import proto "github.com/golang/protobuf/proto"
+import fmt "fmt"
+import math "math"
+
+// Reference imports to suppress errors if they are not otherwise used.
+var _ = proto.Marshal
+var _ = fmt.Errorf
+var _ = math.Inf
+
+// This is a compile-time assertion to ensure that this generated file
+// is compatible with the proto package it is being compiled against.
+const _ = proto.ProtoPackageIsVersion1
+
+// A generic empty message that you can re-use to avoid defining duplicated
+// empty messages in your APIs. A typical example is to use it as the request
+// or the response type of an API method. For instance:
+//
+//     service Foo {
+//       rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty);
+//     }
+//
+// The JSON representation for `Empty` is empty JSON object `{}`.
+type Empty struct {
+}
+
+func (m *Empty) Reset()                    { *m = Empty{} }
+func (m *Empty) String() string            { return proto.CompactTextString(m) }
+func (*Empty) ProtoMessage()               {}
+func (*Empty) Descriptor() ([]byte, []int) { return fileDescriptor0, []int{0} }
+
+func init() {
+	proto.RegisterType((*Empty)(nil), "google.protobuf.Empty")
+}
+
+var fileDescriptor0 = []byte{
+	// 148 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xe2, 0x32, 0x4a, 0xcf, 0x2c, 0xc9,
+	0x28, 0x4d, 0xd2, 0x4b, 0xce, 0xcf, 0xd5, 0x4f, 0xcf, 0xcf, 0x49, 0xcc, 0x4b, 0xd7, 0x2f, 0x28,
+	0xca, 0x2f, 0xc9, 0x4f, 0x2a, 0x4d, 0xd3, 0x2f, 0xa9, 0x2c, 0x48, 0x2d, 0xd6, 0x4f, 0xcd, 0x2d,
+	0x28, 0xa9, 0x84, 0x90, 0x7a, 0x60, 0x29, 0x21, 0xfe, 0xf4, 0xfc, 0xfc, 0xf4, 0x9c, 0x54, 0x3d,
+	0x98, 0x42, 0x25, 0x76, 0x2e, 0x56, 0x57, 0x90, 0xbc, 0x53, 0x38, 0x97, 0x30, 0xd0, 0x20, 0x3d,
+	0x34, 0x79, 0x27, 0x2e, 0xb0, 0x6c, 0x00, 0x88, 0x1b, 0xc0, 0x18, 0xc5, 0x0a, 0x36, 0x6b, 0x01,
+	0x23, 0xe3, 0x0f, 0x46, 0xc6, 0x45, 0x4c, 0xcc, 0xee, 0x01, 0x4e, 0xab, 0x98, 0xe4, 0xdc, 0x21,
+	0x5a, 0x02, 0xa0, 0x5a, 0xf4, 0xc2, 0x53, 0x73, 0x72, 0xbc, 0xf3, 0xf2, 0xcb, 0xf3, 0x42, 0x40,
+	0x8e, 0x48, 0x62, 0x03, 0x9b, 0x65, 0x0c, 0x08, 0x00, 0x00, 0xff, 0xff, 0x29, 0x06, 0xae, 0x32,
+	0xaf, 0x00, 0x00, 0x00,
+}
diff --git a/types/empty/empty.proto b/types/empty/empty.proto
new file mode 100644
index 0000000..106af23
--- /dev/null
+++ b/types/empty/empty.proto
@@ -0,0 +1,53 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+syntax = "proto3";
+
+package google.protobuf;
+option go_package = "empty";
+
+option csharp_namespace = "Google.Protobuf.WellKnownTypes";
+option java_package = "com.google.protobuf";
+option java_outer_classname = "EmptyProto";
+option java_multiple_files = true;
+option java_generate_equals_and_hash = true;
+option objc_class_prefix = "GPB";
+option cc_enable_arenas = true;
+
+// A generic empty message that you can re-use to avoid defining duplicated
+// empty messages in your APIs. A typical example is to use it as the request
+// or the response type of an API method. For instance:
+//
+//     service Foo {
+//       rpc Bar(google.protobuf.Empty) returns (google.protobuf.Empty);
+//     }
+//
+// The JSON representation for `Empty` is empty JSON object `{}`.
+message Empty {}
diff --git a/types/regen.sh b/types/regen.sh
new file mode 100755
index 0000000..653c01c
--- /dev/null
+++ b/types/regen.sh
@@ -0,0 +1,67 @@
+#!/bin/bash -e
+#
+# This script fetches and rebuilds the "well-known types" protocol buffers.
+# To run this you will need protoc and goprotobuf installed;
+# see https://github.com/golang/protobuf for instructions.
+# You also need Go and Git installed.
+
+PKG=github.com/golang/protobuf/types
+UPSTREAM=https://github.com/google/protobuf
+UPSTREAM_SUBDIR=src/google/protobuf
+PROTO_FILES='
+  any.proto
+  duration.proto
+  empty.proto
+'
+
+function die() {
+  echo 1>&2 $*
+  exit 1
+}
+
+# Sanity check that the right tools are accessible.
+for tool in go git protoc protoc-gen-go; do
+  q=$(which $tool) || die "didn't find $tool"
+  echo 1>&2 "$tool: $q"
+done
+
+tmpdir=$(mktemp -d -t regen-wkt.XXXXXX)
+trap 'rm -rf $tmpdir' EXIT
+
+echo -n 1>&2 "finding package dir... "
+pkgdir=$(go list -f '{{.Dir}}' $PKG)
+echo 1>&2 $pkgdir
+base=$(echo $pkgdir | sed "s,/$PKG\$,,")
+echo 1>&2 "base: $base"
+cd $base
+
+echo 1>&2 "fetching latest protos... "
+git clone -q $UPSTREAM $tmpdir
+# Pass 1: build mapping from upstream filename to our filename.
+declare -A filename_map
+for f in $(cd $PKG && find * -name '*.proto'); do
+  echo -n 1>&2 "looking for latest version of $f... "
+  up=$(cd $tmpdir/$UPSTREAM_SUBDIR && find * -name $(basename $f))
+  echo 1>&2 $up
+  if [ $(echo $up | wc -w) != "1" ]; then
+    die "not exactly one match"
+  fi
+  filename_map[$up]=$f
+done
+# Pass 2: copy files, making necessary adjustments.
+for up in "${!filename_map[@]}"; do
+  f=${filename_map[$up]}
+  shortname=$(basename $f | sed 's,\.proto$,,')
+  cat $tmpdir/$UPSTREAM_SUBDIR/$up |
+    # Adjust proto package.
+    # TODO(dsymonds): Upstream the go_package option instead.
+    sed '/^package /a option go_package = "'${shortname}'";' |
+    cat > $PKG/$f
+done
+
+# Run protoc once per package.
+for dir in $(find $PKG -name '*.proto' | xargs dirname | sort | uniq); do
+  echo 1>&2 "* $dir"
+  protoc --go_out=. $dir/*.proto
+done
+echo 1>&2 "All OK"