diff --git a/lib/go/thrift/debug_protocol.go b/lib/go/thrift/debug_protocol.go
index a092003..875844b 100644
--- a/lib/go/thrift/debug_protocol.go
+++ b/lib/go/thrift/debug_protocol.go
@@ -25,9 +25,27 @@
 )
 
 type TDebugProtocol struct {
-	Delegate  TProtocol
-	LogPrefix string
+	// Required. The actual TProtocol to do the read/write.
+	Delegate TProtocol
+
+	// Optional. The logger and prefix to log all the args/return values
+	// from Delegate TProtocol calls.
+	//
+	// If Logger is nil, StdLogger using stdlib log package with os.Stderr
+	// will be used. If disable logging is desired, set Logger to NopLogger
+	// explicitly instead of leaving it as nil/unset.
 	Logger    Logger
+	LogPrefix string
+
+	// Optional. An TProtocol to duplicate everything read/written from Delegate.
+	//
+	// A typical use case of this is to use TSimpleJSONProtocol wrapping
+	// TMemoryBuffer in a middleware to json logging requests/responses.
+	//
+	// This feature is not available from TDebugProtocolFactory. In order to
+	// use it you have to construct TDebugProtocol directly, or set DuplicateTo
+	// field after getting a TDebugProtocol from the factory.
+	DuplicateTo TProtocol
 }
 
 type TDebugProtocolFactory struct {
@@ -73,217 +91,346 @@
 func (tdp *TDebugProtocol) WriteMessageBegin(ctx context.Context, name string, typeId TMessageType, seqid int32) error {
 	err := tdp.Delegate.WriteMessageBegin(ctx, name, typeId, seqid)
 	tdp.logf("%sWriteMessageBegin(name=%#v, typeId=%#v, seqid=%#v) => %#v", tdp.LogPrefix, name, typeId, seqid, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMessageBegin(ctx, name, typeId, seqid)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteMessageEnd(ctx context.Context) error {
 	err := tdp.Delegate.WriteMessageEnd(ctx)
 	tdp.logf("%sWriteMessageEnd() => %#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMessageEnd(ctx)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteStructBegin(ctx context.Context, name string) error {
 	err := tdp.Delegate.WriteStructBegin(ctx, name)
 	tdp.logf("%sWriteStructBegin(name=%#v) => %#v", tdp.LogPrefix, name, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteStructBegin(ctx, name)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteStructEnd(ctx context.Context) error {
 	err := tdp.Delegate.WriteStructEnd(ctx)
 	tdp.logf("%sWriteStructEnd() => %#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteStructEnd(ctx)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteFieldBegin(ctx context.Context, name string, typeId TType, id int16) error {
 	err := tdp.Delegate.WriteFieldBegin(ctx, name, typeId, id)
 	tdp.logf("%sWriteFieldBegin(name=%#v, typeId=%#v, id%#v) => %#v", tdp.LogPrefix, name, typeId, id, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteFieldBegin(ctx, name, typeId, id)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteFieldEnd(ctx context.Context) error {
 	err := tdp.Delegate.WriteFieldEnd(ctx)
 	tdp.logf("%sWriteFieldEnd() => %#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteFieldEnd(ctx)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteFieldStop(ctx context.Context) error {
 	err := tdp.Delegate.WriteFieldStop(ctx)
 	tdp.logf("%sWriteFieldStop() => %#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteFieldStop(ctx)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteMapBegin(ctx context.Context, keyType TType, valueType TType, size int) error {
 	err := tdp.Delegate.WriteMapBegin(ctx, keyType, valueType, size)
 	tdp.logf("%sWriteMapBegin(keyType=%#v, valueType=%#v, size=%#v) => %#v", tdp.LogPrefix, keyType, valueType, size, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMapBegin(ctx, keyType, valueType, size)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteMapEnd(ctx context.Context) error {
 	err := tdp.Delegate.WriteMapEnd(ctx)
 	tdp.logf("%sWriteMapEnd() => %#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMapEnd(ctx)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteListBegin(ctx context.Context, elemType TType, size int) error {
 	err := tdp.Delegate.WriteListBegin(ctx, elemType, size)
 	tdp.logf("%sWriteListBegin(elemType=%#v, size=%#v) => %#v", tdp.LogPrefix, elemType, size, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteListBegin(ctx, elemType, size)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteListEnd(ctx context.Context) error {
 	err := tdp.Delegate.WriteListEnd(ctx)
 	tdp.logf("%sWriteListEnd() => %#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteListEnd(ctx)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteSetBegin(ctx context.Context, elemType TType, size int) error {
 	err := tdp.Delegate.WriteSetBegin(ctx, elemType, size)
 	tdp.logf("%sWriteSetBegin(elemType=%#v, size=%#v) => %#v", tdp.LogPrefix, elemType, size, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteSetBegin(ctx, elemType, size)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteSetEnd(ctx context.Context) error {
 	err := tdp.Delegate.WriteSetEnd(ctx)
 	tdp.logf("%sWriteSetEnd() => %#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteSetEnd(ctx)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteBool(ctx context.Context, value bool) error {
 	err := tdp.Delegate.WriteBool(ctx, value)
 	tdp.logf("%sWriteBool(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteBool(ctx, value)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteByte(ctx context.Context, value int8) error {
 	err := tdp.Delegate.WriteByte(ctx, value)
 	tdp.logf("%sWriteByte(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteByte(ctx, value)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteI16(ctx context.Context, value int16) error {
 	err := tdp.Delegate.WriteI16(ctx, value)
 	tdp.logf("%sWriteI16(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteI16(ctx, value)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteI32(ctx context.Context, value int32) error {
 	err := tdp.Delegate.WriteI32(ctx, value)
 	tdp.logf("%sWriteI32(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteI32(ctx, value)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteI64(ctx context.Context, value int64) error {
 	err := tdp.Delegate.WriteI64(ctx, value)
 	tdp.logf("%sWriteI64(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteI64(ctx, value)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteDouble(ctx context.Context, value float64) error {
 	err := tdp.Delegate.WriteDouble(ctx, value)
 	tdp.logf("%sWriteDouble(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteDouble(ctx, value)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteString(ctx context.Context, value string) error {
 	err := tdp.Delegate.WriteString(ctx, value)
 	tdp.logf("%sWriteString(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteString(ctx, value)
+	}
 	return err
 }
 func (tdp *TDebugProtocol) WriteBinary(ctx context.Context, value []byte) error {
 	err := tdp.Delegate.WriteBinary(ctx, value)
 	tdp.logf("%sWriteBinary(value=%#v) => %#v", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteBinary(ctx, value)
+	}
 	return err
 }
 
 func (tdp *TDebugProtocol) ReadMessageBegin(ctx context.Context) (name string, typeId TMessageType, seqid int32, err error) {
 	name, typeId, seqid, err = tdp.Delegate.ReadMessageBegin(ctx)
 	tdp.logf("%sReadMessageBegin() (name=%#v, typeId=%#v, seqid=%#v, err=%#v)", tdp.LogPrefix, name, typeId, seqid, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMessageBegin(ctx, name, typeId, seqid)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadMessageEnd(ctx context.Context) (err error) {
 	err = tdp.Delegate.ReadMessageEnd(ctx)
 	tdp.logf("%sReadMessageEnd() err=%#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMessageEnd(ctx)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadStructBegin(ctx context.Context) (name string, err error) {
 	name, err = tdp.Delegate.ReadStructBegin(ctx)
 	tdp.logf("%sReadStructBegin() (name%#v, err=%#v)", tdp.LogPrefix, name, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteStructBegin(ctx, name)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadStructEnd(ctx context.Context) (err error) {
 	err = tdp.Delegate.ReadStructEnd(ctx)
 	tdp.logf("%sReadStructEnd() err=%#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteStructEnd(ctx)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadFieldBegin(ctx context.Context) (name string, typeId TType, id int16, err error) {
 	name, typeId, id, err = tdp.Delegate.ReadFieldBegin(ctx)
 	tdp.logf("%sReadFieldBegin() (name=%#v, typeId=%#v, id=%#v, err=%#v)", tdp.LogPrefix, name, typeId, id, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteFieldBegin(ctx, name, typeId, id)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadFieldEnd(ctx context.Context) (err error) {
 	err = tdp.Delegate.ReadFieldEnd(ctx)
 	tdp.logf("%sReadFieldEnd() err=%#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteFieldEnd(ctx)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadMapBegin(ctx context.Context) (keyType TType, valueType TType, size int, err error) {
 	keyType, valueType, size, err = tdp.Delegate.ReadMapBegin(ctx)
 	tdp.logf("%sReadMapBegin() (keyType=%#v, valueType=%#v, size=%#v, err=%#v)", tdp.LogPrefix, keyType, valueType, size, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMapBegin(ctx, keyType, valueType, size)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadMapEnd(ctx context.Context) (err error) {
 	err = tdp.Delegate.ReadMapEnd(ctx)
 	tdp.logf("%sReadMapEnd() err=%#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteMapEnd(ctx)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadListBegin(ctx context.Context) (elemType TType, size int, err error) {
 	elemType, size, err = tdp.Delegate.ReadListBegin(ctx)
 	tdp.logf("%sReadListBegin() (elemType=%#v, size=%#v, err=%#v)", tdp.LogPrefix, elemType, size, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteListBegin(ctx, elemType, size)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadListEnd(ctx context.Context) (err error) {
 	err = tdp.Delegate.ReadListEnd(ctx)
 	tdp.logf("%sReadListEnd() err=%#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteListEnd(ctx)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadSetBegin(ctx context.Context) (elemType TType, size int, err error) {
 	elemType, size, err = tdp.Delegate.ReadSetBegin(ctx)
 	tdp.logf("%sReadSetBegin() (elemType=%#v, size=%#v, err=%#v)", tdp.LogPrefix, elemType, size, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteSetBegin(ctx, elemType, size)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadSetEnd(ctx context.Context) (err error) {
 	err = tdp.Delegate.ReadSetEnd(ctx)
 	tdp.logf("%sReadSetEnd() err=%#v", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteSetEnd(ctx)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadBool(ctx context.Context) (value bool, err error) {
 	value, err = tdp.Delegate.ReadBool(ctx)
 	tdp.logf("%sReadBool() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteBool(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadByte(ctx context.Context) (value int8, err error) {
 	value, err = tdp.Delegate.ReadByte(ctx)
 	tdp.logf("%sReadByte() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteByte(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadI16(ctx context.Context) (value int16, err error) {
 	value, err = tdp.Delegate.ReadI16(ctx)
 	tdp.logf("%sReadI16() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteI16(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadI32(ctx context.Context) (value int32, err error) {
 	value, err = tdp.Delegate.ReadI32(ctx)
 	tdp.logf("%sReadI32() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteI32(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadI64(ctx context.Context) (value int64, err error) {
 	value, err = tdp.Delegate.ReadI64(ctx)
 	tdp.logf("%sReadI64() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteI64(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadDouble(ctx context.Context) (value float64, err error) {
 	value, err = tdp.Delegate.ReadDouble(ctx)
 	tdp.logf("%sReadDouble() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteDouble(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadString(ctx context.Context) (value string, err error) {
 	value, err = tdp.Delegate.ReadString(ctx)
 	tdp.logf("%sReadString() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteString(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) ReadBinary(ctx context.Context) (value []byte, err error) {
 	value, err = tdp.Delegate.ReadBinary(ctx)
 	tdp.logf("%sReadBinary() (value=%#v, err=%#v)", tdp.LogPrefix, value, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.WriteBinary(ctx, value)
+	}
 	return
 }
 func (tdp *TDebugProtocol) Skip(ctx context.Context, fieldType TType) (err error) {
 	err = tdp.Delegate.Skip(ctx, fieldType)
 	tdp.logf("%sSkip(fieldType=%#v) (err=%#v)", tdp.LogPrefix, fieldType, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.Skip(ctx, fieldType)
+	}
 	return
 }
 func (tdp *TDebugProtocol) Flush(ctx context.Context) (err error) {
 	err = tdp.Delegate.Flush(ctx)
 	tdp.logf("%sFlush() (err=%#v)", tdp.LogPrefix, err)
+	if tdp.DuplicateTo != nil {
+		tdp.DuplicateTo.Flush(ctx)
+	}
 	return
 }