Download tarball from zig download index (#2)

* Download tarball from zig download index

* try this

* Remove promisify

* Revert "try this"

This reverts commit e6ecfb58ed.

node_modules/simple-concat/test/basic.js

@@ -0,0 +1,41 @@
+var concat = require('../')
+var stream = require('stream')
+var test = require('tape')
+
+test('basic', function (t) {
+  t.plan(2)
+  var s = new stream.PassThrough()
+  concat(s, function (err, buf) {
+    t.error(err)
+    t.deepEqual(buf, new Buffer('abc123456789'))
+  })
+  s.write('abc')
+  setTimeout(function () {
+    s.write('123')
+  }, 10)
+  setTimeout(function () {
+    s.write('456')
+  }, 20)
+  setTimeout(function () {
+    s.end('789')
+  }, 30)
+})
+
+test('error', function (t) {
+  t.plan(2)
+  var s = new stream.PassThrough()
+  concat(s, function (err, buf) {
+    t.ok(err, 'got expected error')
+    t.ok(!buf)
+  })
+  s.write('abc')
+  setTimeout(function () {
+    s.write('123')
+  }, 10)
+  setTimeout(function () {
+    s.write('456')
+  }, 20)
+  setTimeout(function () {
+    s.emit('error', new Error('error'))
+  }, 30)
+})