code: function (id, options, callback) {
              var args = arguments,
                  retry = false,
                  handler;
  
              if (typeof options === 'function') {
                  callback = options;
              } else {
                  options = extend({}, options);
                  retry = options.retry;
              }
  
              retry = (retry === true) && function () {
                  this.delete.apply(this, args);
              }.bind(this);
  
              handler = createResponseHandler(callback, [204], true, retry);
  
              return req(client.documentsURL + '/' + id, { method: 'DELETE' }, handler);
          }
docs: Delete a single document
  @param   {String}   id               The document uuid
  @param   {Object}   [options]        Delete options
  @param   {boolean}  [options.retry]  Whether to retry the request after 'retry-after' seconds if the retry-after header is sent
  @param   {Function} [callback]       A callback to call with the response data (or error)
  @returns {Request}