docs: function sendCommand(method, url, payload, skipQueue) {
      if (!self.connected) {
        debug('Queueing %s %s', method, url);
        return new P(function(resolve, reject) {
          var p = P.method(function() {
            debug('Dequeueing %s %s', method, url);
            return _sendCommand(method, url, payload)
              .then(resolve)
              .catch(reject);
          });
          if (skipQueue) {
            pendingCommands.splice(0, 0, p);
          } else {
            pendingCommands.push(p);
          }
        });
      }
      return _sendCommand(method, url, payload);
    }