code: function loadClass(className) {
    var Class = Classes[className];
  
    if (Class !== undefined) {
      return Class;
    }
  
    // This uses a switch for static require analysis
    switch (className) {
      case 'Connection':
        Class = require('./lib/Connection');
        break;
      case 'ConnectionConfig':
        Class = require('./lib/ConnectionConfig');
        break;
      case 'Pool':
        Class = require('./lib/Pool');
        break;
      case 'PoolCluster':
        Class = require('./lib/PoolCluster');
        break;
      case 'PoolConfig':
        Class = require('./lib/PoolConfig');
        break;
      case 'SqlString':
        Class = require('./lib/protocol/SqlString');
        break;
      case 'Types':
        Class = require('./lib/protocol/constants/types');
        break;
      default:
        throw new Error('Cannot find class \'' + className + '\'');
    }
  
    // Store to prevent invoking require()
    Classes[className] = Class;
  
    return Class;
  }
docs: Load the given class.
  @param {string} className Name of class to default
  @return {function|object} Class constructor or exports
  @private