function streamFactory( options ) {
	var opts;
	if ( arguments.length ) {
		if ( !isObject( options ) ) {
			throw new TypeError( format( 'invalid argument. Options argument must be an object. Value: `%s`.', options ) );
		}
		opts = assign( {}, options );
	} else {
		opts = {};
	}
	return createStream;

	/**
	* Creates a transform stream.
	*
	* @private
	* @param {Function} transform - callback to invoke upon receiving a new chunk
	* @param {Function} [flush] - callback to invoke after receiving all chunks and prior to the stream closing
	* @throws {TypeError} must provide valid options
	* @throws {TypeError} transform callback must be a function
	* @throws {TypeError} flush callback must be a function
	* @returns {TransformStream} transform stream
	*/
	function createStream( transform, flush ) {
		opts.transform = transform;
		if ( arguments.length > 1 ) {
			opts.flush = flush;
		} else {
			delete opts.flush; // clear any previous `flush`
		}
		return new Stream( opts );
	}
}
Creates a reusable transform stream factory.

@param {Options} [options] - stream options
@param {boolean} [options.objectMode=false] - specifies whether a stream should operate in object mode
@param {(string|null)} [options.encoding=null] - specifies how `Buffer` objects should be decoded to `strings`
@param {NonNegativeNumber} [options.highWaterMark] - specifies the `Buffer` level for when `write()` starts returning `false`
@param {boolean} [options.allowHalfOpen=false] - specifies whether the stream should remain open even if one side ends
@param {boolean} [options.decodeStrings=true] - specifies whether to decode `strings` into `Buffer` objects when writing
@throws {TypeError} options argument must be an object
@returns {Function} transform stream factory

@example
function transform( chunk, enc, clbk ) {
    clbk( null, chunk.toString()+'\n' );
}

var opts = {
    'objectMode': true,
    'encoding': 'utf8',
    'highWaterMark': 64,
    'decodeStrings': false
};

var factory = streamFactory( opts );

// Create 10 identically configured streams...
var streams = [];
var i;
for ( i = 0; i < 10; i++ ) {
    streams.push( factory( transform ) );
}