code: public byte[] getPayload(int payloadStart, int payloadSize) {
          byte[] payloadBuffer = new byte[payloadSize];
          System.arraycopy(currentBuffer, payloadStart, payloadBuffer, 0, payloadSize);
          return payloadBuffer;
      }
docs: Returns a portion of the internal buffer
  @param payloadStart
  @param payloadSize
  @return