Get the ALPN protocol that was negotiated, if any. Stores a pointer to a
borrowed buffer of bytes, and that buffer's len, in the output parameters.
The borrow lives as long as the connection.
If the connection is still handshaking, or no ALPN protocol was negotiated,
stores NULL and 0 in the output parameters.
The provided pointer is valid until the next mutating function call
affecting the connection. A mutating function call is one where the
first argument has type struct rustls_connection * (as opposed to
const struct rustls_connection *).
<https://www.iana.org/assignments/tls-parameters/>
<https://docs.rs/rustls/0.20.0/rustls/enum.Connection.html#method.alpn_protocol>
Get the ALPN protocol that was negotiated, if any. Stores a pointer to a borrowed buffer of bytes, and that buffer's len, in the output parameters. The borrow lives as long as the connection. If the connection is still handshaking, or no ALPN protocol was negotiated, stores NULL and 0 in the output parameters. The provided pointer is valid until the next mutating function call affecting the connection. A mutating function call is one where the first argument has type struct rustls_connection * (as opposed to const struct rustls_connection *). <https://www.iana.org/assignments/tls-parameters/> <https://docs.rs/rustls/0.20.0/rustls/enum.Connection.html#method.alpn_protocol>