transform-buffer-stream.js

 var BufferStream = function () {
        stream.Transform.apply(this, arguments);
        this.sumanReady = false;
        this.buffer = [];
    };

    util.inherits(BufferStream, stream.Transform);

    BufferStream.prototype._transform = function (chunk, encoding, done) {
        // custom buffering logic
        // ie. add chunk to this.buffer, check buffer size, etc.

        if (this.sumanReady) {
            this.push(chunk ? String(chunk) : null);
        }
        else {
            this.buffer.push(chunk ? String(chunk) : null);
        }

        done()
    };

    BufferStream.prototype.pipe = function (destination, options) {
        var res = BufferStream.super_.prototype.pipe.apply(this, arguments);
        this.buffer.forEach(function (b) {
            res.write(String(b));
        });
        this.sumanReady = true;
        return res;
    };

    // strm.cork();
    return new BufferStream();