UnhandledRejection in subscribeEvents when connection is closed before receiving response

[Jason]

Issue #65 has reappeared or something very similar to it.

https://gist.github.com/zachowj/3bad002cd0ba3b5cd61dbfd47aecb3b5 is a demo of error in action.

Last working with v3.1.6
Tested and fails with v3.2.0 and v4.2.0

[Paulus Schoutsen]

Without testing it, I suspect it was introduced in #74 when fixing #71.

[Paulus Schoutsen]

Confirmed it's introduced in #74.