function createStream( options ) {
	var stream;
	var bench;
	var opts;
	if ( arguments.length ) {
		opts = options;
	} else {
		opts = {};
	}
	// If we have already created a harness, calling this function simply creates another results stream...
	if ( harness.cached ) {
		bench = harness();
		return bench.createStream( opts );
	}
	stream = new TransformStream( opts );
	opts.stream = stream;

	// Create a harness which uses the created output stream:
	harness( opts, done );

	return stream;
}
Creates a results stream.

@private
@param {Options} [options] - stream options
@throws {Error} must provide valid stream options
@returns {TransformStream} results stream