code: function receive ( str ){
      ping(); // clear/schedule next ping
      var msg = typeof str === 'string' ? JSON.parse( str ) : str;
      b9.emit('rtm.read', msg, replyTo( null ) );
      // acknowledge that a pending message was sent successfully
      if ( msg.reply_to ){
        delete pending[ msg.reply_to ];
      }
      else if ( msg.type != null ){
        b9.emit( msg.type, msg, replyTo( msg.channel ) );
      }
    }
docs: handle a websocket message
  @private method