storage: use fast-crc32c conditionally (#1367)

lib/storage/bucket.js

@@ -923,6 +923,11 @@ Bucket.prototype.makePublic = function(options, callback) {
  * `options.resumable`. *Resumable uploads are enabled by default if your input
  * file is larger than 5 MB.*
  *
+ * For faster crc32c computation, you must manually install
+ * [`fast-crc32c`](http://www.gitnpm.com/fast-crc32c):
+ *
+ *     $ npm install --save fast-crc32c
+ *
  * @resource [Upload Options (Simple or Resumable)]{@link https://cloud.google.com/storage/docs/json_api/v1/how-tos/upload#uploads}
  * @resource [Objects: insert API Documentation]{@link https://cloud.google.com/storage/docs/json_api/v1/objects/insert}
  *

lib/storage/file.js

@@ -409,6 +409,11 @@ File.prototype.copy = function(destination, callback) {
  * "CONTENT_DOWNLOAD_MISMATCH". If you receive this error, the best recourse is
  * to try downloading the file again.
  *
+ * For faster crc32c computation, you must manually install
+ * [`fast-crc32c`](http://www.gitnpm.com/fast-crc32c):
+ *
+ *     $ npm install --save fast-crc32c
+ *
  * NOTE: Readable streams will emit the `end` event when the file is fully
  * downloaded.
  *
@@ -708,6 +713,11 @@ File.prototype.createResumableUpload = function(options, callback) {
  * Resumable uploads are automatically enabled and must be shut off explicitly
  * by setting `options.resumable` to `false`.
  *
+ * For faster crc32c computation, you must manually install
+ * [`fast-crc32c`](http://www.gitnpm.com/fast-crc32c):
+ *
+ *     $ npm install --save fast-crc32c
+ *
  * NOTE: Writable streams will emit the `finish` event when the file is fully
  * uploaded.
  *

package.json

@@ -104,7 +104,7 @@
     "google-auto-auth": "^0.2.4",
     "google-proto-files": "^0.1.1",
     "grpc": "^0.14.1",
-    "hash-stream-validation": "^0.1.0",
+    "hash-stream-validation": "^0.2.1",
     "is": "^3.0.1",
     "lodash.flatten": "^4.2.0",
     "methmeth": "^1.0.0",