function mapValuesAsync( obj, done ) {
		if ( typeof obj !== 'object' || obj === null ) {
			throw new TypeError( format( 'invalid argument. First argument must be an object. Value: `%s`.', obj ) );
		}
		if ( !isFunction( done ) ) {
			throw new TypeError( format( 'invalid argument. Last argument must be a function. Value: `%s`.', done ) );
		}
		return limit( obj, opts, f, clbk );

		/**
		* Callback invoked upon completion.
		*
		* @private
		* @param {*} [error] - error
		* @param {Object} [out] - output object
		* @returns {void}
		*/
		function clbk( error, out ) {
			if ( error ) {
				return done( error );
			}
			done( null, out );
		}
	}
Maps values from one object to a new object having the same keys.

@private
@param {Object} obj - source object
@param {Callback} done - function to invoke upon completion
@throws {TypeError} first argument must be an object
@throws {TypeError} last argument must be a function
@returns {void}