docs: function buildRequestor(clientOptions) {
    if(clientOptions.requestor) return clientOptions.requestor;
  
    var requestorConfig =
      _.pick(clientOptions, 'maxRetryDurationSeconds', 'calcRetryBackoff');
  
    if(requestorConfig.maxRetryDurationSeconds)
      requestorConfig.maxRetryDurationMillis = requestorConfig.maxRetryDurationSeconds * 1000;
  
    requestorConfig.logger = buildLogger(clientOptions);
  
    return require('./lib/utils/httpRequestor.js')
      .create(requestorConfig);
  }