Function serialize

src/common/http.cpp:107–124

namespace internal {

string serialize(
    ContentType contentType,
    const google::protobuf::Message& message)
{
  switch (contentType) {
    case ContentType::PROTOBUF: {
      return message.SerializeAsString();
    }
    case ContentType::JSON: {
      return jsonify(JSON::Protobuf(message));
    }
    case ContentType::RECORDIO: {
      LOG(FATAL) << "Serializing a RecordIO stream is not supported";
    }
  }

  UNREACHABLE();
}


bool streamingMediaType(ContentType contentType)