Application-Layer Protocol Negotiation (ALPN) protocols to announce to
the client. If not specified, no ALPN extension will be included in the
TLS handshake.
NOTE this is part of the native HTTP server in Deno 1.9 or later,
which requires the --unstable flag to be available.
secure: true
optional
signal: AbortSignal
An optional abort signal which can be used to close the listener.