Wire pStats into sub-handlers to capture real byte counts from QUIC
streams instead of the dummy listener conn. Resolve target address and
validate capsule-protocol after authentication instead of before 200
response to prevent dead tunnels and unauthenticated probing. Merge
pending observer events rather than replacing on consecutive failures.
Add idle read timeout to TCP tunnel relay. Add doc comments on exported
symbols and NewHandler.
Implement UDP tunneling over HTTP/3 using HTTP Datagrams (RFC 9297):
- Add masque handler for server-side CONNECT-UDP
- Add masque connector and h3-masque dialer for client-side
- Add enableDatagrams option to HTTP/3 listener
- Add shared utilities for datagram connections and path parsing
Resource management and connection caching:
- Add deferred stream cleanup in connector on error paths
- Add IsClosed() and Close() methods to Client for proper session management
- Clean up stale cached clients in dialer before reuse
- Close underlying stream when DatagramConn is closed
- Move RequestStream opening from connector to dialer to enable dead
connection detection and cache invalidation (follows QUIC dialer pattern)
ginuerzh
David Manouchehri