HTTP/2: lingering close after GOAWAY. After sending the GOAWAY frame, a connection is now closed using the lingering close mechanism. This allows for the reliable delivery of the GOAWAY frames, while also fixing connection resets observed when http2_max_requests is reached (ticket #1250), or with graceful shutdown (ticket #1544), when some additional data from the client is received on a fully closed connection. For HTTP/2, the settings lingering_close, lingering_timeout, and lingering_time are taken from the "server" level.