Close frame spanning multiple packets is not handled correctly

[mwm-twx]

• I've searched for any related issues and avoided creating a duplicate
  issue.

Description

A close frame which has been split over multiple TCP packets, for example

is not handled correctly. The payload is never read and conclude event not emitted.

Reproducible in:

• version: 6.1.2
• Node.js version(s): 10.12
• OS version(s): Linux; Fedora 29

Steps to reproduce:

1. Establish a websocket session

2. Send a close frame from the server as two separate packets

Expected result:

1. Close frame is parsed correctly and conclude event is emitted from receiver

Actual result:

1. Close frame is not parsed and conclude is never emitted