do not try to read from websocket after sending and receiving the clo…

[MichaelSB]

This is a fix for #446

1. for server-side close (segfault): after handling the close frame from the client in handle_fragment, shutdown the connection and return false to the caller, signalling no further reads should be done
2. for client-side close (failing read after close, causing error-handler being called): just destroy the connection in do_read if we both sent and received the close frame (according to https://datatracker.ietf.org/doc/html/rfc6455#section-5.5.1)

[The-EDev]

I'm guessing we're preventing do_read() from running after handling the close frame because the if (has_sent_close_ && has_recv_close_) block references the adaptor which would cause another segfault.

On face value I can't see anything wrong, I"ll test it with the example you provided in #446.

[The-EDev]

Everything seems to be alright.

Thank you very much @MichaelSB for finding and fixing this problem, and I'm sorry I couldn't help much with it.

[MichaelSB]

Yes, that's the reason for preventing do_read entirely. Thanks for merging. And don't worry :) I really like crow and trying to fix problems I find is the least I can do.