@Override
  public String toString() {
    return super.toString()
        + "; chunkLength= " + chunkLength
        + "; lastChunk=" + lastChunk;
  }
Initially false; set to true once the message header is sent; set back to false when last chunk
is sent.
geode-core/src/main/java/org/apache/geode/internal/cache/tier/sockets/ChunkedMessage.java