on_chunk_header</span></code></a>
                </p>
              </td>
<td>
                <p>
                  Set a callback to be invoked on each chunk header.
                </p>
                <p>
                  The callback will be invoked once for every chunk in the message
                  payload, as well as once for the last chunk. The invocation happens
                  after the chunk header is available but before any body octets
                  have been parsed.
                