Document lifetime of the DTLS session #1036
Description
Like in #1035 I haven't found any documentation for the following practice. JSEP or the security RFC seem like the right place to document it.
After the DTLS handshake is done, the DTLS session should be kept open for the whole duration of the "session".
The rationale is (again) that browsers might renegotiate and use data channels. Also "closing" the session by sending a close alert leads to a failed DtlsTransport which leads to a connectionstate of failed.
I do believe that all browsers behave like this already so this is just a clarification.