Support synchronisation in send_message.
Support synchronisation in send_message.

michaelmaguire/twosidedsearch,michaelmaguire/twosidedsearch,michaelmaguire/twosidedsearch,michaelmaguire/twosidedsearch,michaelmaguire/twosidedsearch,michaelmaguire/twosidedsearch,michaelmaguire/twosidedsearch,michaelmaguire/twosidedsearch