lib/middleware.js
function Transformer( file, res ) {
			stream.Transform.call( this );

			this.file = file;
			this.res = res;
			this.chunks = [];
		}
function Transformer( file, res ) {
			stream.Transform.call( this );

			this.file = file;
			this.res = res;
			this.chunks = [];
		}
function Transformer ( file , res ) { stream . Transform . call ( this ) ; this . file = file ; this . res = res ; this . chunks = [ ] ; }
Transofrms the code from an incomming stream and outputs the code instrumented by Istanbul
@param {String} file File name used by Istanbul
@param {Object} res  HTTP response
Transofrms the code from an incomming stream and outputs the code instrumented by Istanbul