Add peek method

index.js

@@ -2,12 +2,14 @@
const Promise = require("bluebird");
const propagateAbort = require("@ppstreams/propagate-abort");
const propagatePeek = require("@ppstreams/propagate-peek");
const { isEndOfStream } = require("@ppstreams/end-of-stream-marker");
module.exports = function greedySinkStream(description, callback) {
	return {
		description: `greedy sink stream (${description})`,
		abort: propagateAbort,
		peek: propagatePeek,
		read: function produceValue_greedySinkStream(source) {
			let lastResult;

package.json

@@ -7,6 +7,7 @@
  "license": "WTFPL OR CC0-1.0",
  "dependencies": {
    "@ppstreams/propagate-abort": "^0.1.2",
    "@ppstreams/propagate-peek": "^0.1.0",
    "bluebird": "^3.5.4"
  }
}