code: def encode_send_message(payload, rq_sa, rs_sa, channel, seq, tracking=1):
      
      req = create_request_by_name('SendMessage')
      req.channel.number = channel
      req.channel.tracking = tracking
      data = encode_message(req)
  
      header = IpmbHeaderReq()
      header.netfn = req.__netfn__
      header.rs_lun = 0
      header.rs_sa = rs_sa
      header.rq_seq = seq
      header.rq_lun = 0
      header.rq_sa = rq_sa
      header.cmd_id = req.__cmdid__
  
      return encode_ipmb_msg(header, data + payload)
docs: Encode a send message command and embedd the message to be send.
  
      payload: the message to be send as bytestring
      rq_sa: the requester source address
      rs_sa: the responder source address
      channel: the channel
      seq: the sequence number
      tracking: tracking
  
      Returns an encode send message as bytestring