core/src/main/java/com/twitter/elephantbird/util/ThriftToDynamicProto.java
public Message.Builder getBuilder(Class<? extends TBase<?, ?>> thriftClass) {
    return messageBuilderMap.get(protoMessageType(thriftClass)).clone();
  }
public Message.Builder getBuilder(Class<? extends TBase<?, ?>> thriftClass) {
    return messageBuilderMap.get(protoMessageType(thriftClass)).clone();
  }
For the given thriftClass, return a Protobufs builder to build a similar protobuf class.
@param thriftClass The thrift class for which the builder is desired.
@return a protobuf message builder