AVCT_MsgReq() function

* Function AVCT_MsgReq * Description Send an AVCTP message to a peer device. In calling * AVCT_MsgReq(), the application should keep track of the * congestion state of AVCTP as communicated with events * AVCT_CONG_IND_EVT and AVCT_UNCONG_IND_EVT. If the * application calls AVCT_MsgReq() when AVCTP is congested * the message may be discarded. The application may make its * first call to AVCT_MsgReq() after it receives an * AVCT_CONNECT_CFM_EVT or AVCT_CONNECT_IND_EVT on control channel or * AVCT_BROWSE_CONN_CFM_EVT or AVCT_BROWSE_CONN_IND_EVT on browsing channel. * p_msg->layer_specific must be set to * AVCT_DATA_CTRL for control channel traffic; * AVCT_DATA_BROWSE for for browse channel traffic. * Returns AVCT_SUCCESS if successful, otherwise error.