index.js
function createLogger(conf, bitwise) {
  conf = conf || {};
  if(conf.json === undefined) conf.json = true;
  return new Logger(conf, bitwise);
}
function createLogger(conf, bitwise) {
  conf = conf || {};
  if(conf.json === undefined) conf.json = true;
  return new Logger(conf, bitwise);
}
Create a Logger and set json configuration
to true if it has not been defined.

Defined for bunyan compatibility.

@param conf The logger configuration.
@param bitwise A boolean indicating that log levels
should use bitwise operators.