code: function srcStream(stream) {
    var pass = through.obj();
    pass.setMaxListeners(0);
  
    var outputstream = duplexify.obj(pass, ms(stream, pass));
    outputstream.setMaxListeners(0);
  
    var isReading = false;
    outputstream.on('pipe', function (src) {
      isReading = true;
      src.on('end', function () {
        isReading = false;
        outputstream.end();
      });
    });
  
    stream.on('end', function () {
      if (!isReading) {
        outputstream.end();
      }
    });
  
    return outputstream;
  }
docs: Wrap a source stream to passthrough any data
  that's being written to it.
  
  ```js
  var src = require('src-stream');
  
  // wrap something that returns a readable stream
  var stream = src(plugin());
  
  fs.createReadStream('./package.json')
  .pipe(stream)
  .on('data', console.log)
  .on('end', function () {
  console.log();
  console.log('Finished');
  console.log();
  });
  ```
  
  @param  {Stream} `stream` Readable stream to be wrapped.
  @return {Stream} Duplex stream to handle reading and writing.
  @api public