Use index singleton and relocate encoder package.

coding/protocol_buffer.go

@@ -0,0 +1,19 @@
+package coding
+
+import (
+	"code.google.com/p/goprotobuf/proto"
+)
+
+type ProtocolBufferEncoder struct {
+	message proto.Message
+}
+
+func (p *ProtocolBufferEncoder) Encode() ([]byte, error) {
+	return proto.Marshal(p.message)
+}
+
+func NewProtocolBufferEncoder(message proto.Message) *ProtocolBufferEncoder {
+	return &ProtocolBufferEncoder{
+		message: message,
+	}
+}