Check if `unpipe` exists on `inputStream` before calling it (#18)
Check if `unpipe` exists on `inputStream` before calling it (#18)

* Check if `unpipe` exists on `inputStream` before calling it

Some streams doesn't implement the `Readable` interface correctly and therefore doesn't have the `unpipe` method attached to them.

Fixes #17.

* Add explanation

sindresorhus/get-stream,sindresorhus/get-stream