index.js
function parallel() {
	var self = this;
	argy(arguments)
		.ifForm('', function() {})
		.ifForm('function', function(callback) {
			self._struct.push({ type: 'parallelArray', payload: [callback] });
		})
		.ifForm('string function', function(id, callback) {
			var payload = {};
			payload[id] = callback;
			self._struct.push({ type: 'parallelArray', payload: payload });
		})
		.ifForm('array', function(tasks) {
			self._struct.push({ type: 'parallelArray', payload: tasks });
		})
		.ifForm('object', function(tasks) {
			self._struct.push({ type: 'parallelObject', payload: tasks });
		})
		// Async library compatibility {{{
		.ifForm('array function', function(tasks, callback) {
			self._struct.push({ type: 'parallelArray', payload: tasks });
			self.end(callback);
		})
		.ifForm('object function', function(tasks, callback) {
			self._struct.push({ type: 'parallelObject', payload: tasks });
			self.end(callback);
		})
		// }}}
		.ifFormElse(function(form) {
			throw new Error('Unknown call style for .parallel(): ' + form);
		})

	return self;
}
function parallel() {
	var self = this;
	argy(arguments)
		.ifForm('', function() {})
		.ifForm('function', function(callback) {
			self._struct.push({ type: 'parallelArray', payload: [callback] });
		})
		.ifForm('string function', function(id, callback) {
			var payload = {};
			payload[id] = callback;
			self._struct.push({ type: 'parallelArray', payload: payload });
		})
		.ifForm('array', function(tasks) {
			self._struct.push({ type: 'parallelArray', payload: tasks });
		})
		.ifForm('object', function(tasks) {
			self._struct.push({ type: 'parallelObject', payload: tasks });
		})
		// Async library compatibility {{{
		.ifForm('array function', function(tasks, callback) {
			self._struct.push({ type: 'parallelArray', payload: tasks });
			self.end(callback);
		})
		.ifForm('object function', function(tasks, callback) {
			self._struct.push({ type: 'parallelObject', payload: tasks });
			self.end(callback);
		})
		// }}}
		.ifFormElse(function(form) {
			throw new Error('Unknown call style for .parallel(): ' + form);
		})

	return self;
}
Queue up a function(s) to execute in parallel
@param {array|Object|function} The function(s) to execute
@return {Object} This chainable object