code: function BaseClient(opts) {
    this.opts = opts || {};
    var self = this;
    this.sendQConcurrency = opts.sendQueueConcurrency || 5;
    this.sendQ = async.queue(function(data, cb) {
      self.doSend(data, cb);
    }, this.sendQConcurrency);
  }
docs: A base implementation for all the clients