Module relayed 

Relayed-transport method (TURN-like) — the last resort, tier 6.

This tier is sharply distinct from the tier-5 hole-punch (super::hole_punch):

Tier	Method	Relay’s role	Relay bandwidth
5	HolePunchMethod	signaling only — brokers a candidate exchange, then the DATA path is peer-to-peer direct	minimal (a few coordination messages)
6	RelayedTransportMethod (this)	carries ALL data — every byte of the peer connection is proxied through the relay (RLY-002 relay_message)	highest — the relay proxies the whole stream

Because tier 6 costs the relay the most bandwidth, it is tried only after the tier-5 hole punch fails: prefer brokering an introduction (hole punch) over proxying the stream (TURN). The crate::strategy enforces this via super::TraversalKind::rank (HolePunch=4 < Relayed=5).

After the relay opens the tunnel, the resulting byte stream is still wrapped in the same mTLS (peer_id = SHA-256(SPKI)) as every other tier — the relay proxies ciphertext it cannot read.

The relay data-plane is abstracted behind RelayedTransport so the method is unit-tested with a mock (no real relay). The production impl — ReservationRelayedTransport — opens an RLY-002 forwarding channel to the target peer THROUGH the node’s persistent relay reservation socket (never a second connection), and hands the caller a RelayTunnel for the byte stream.

Structs

RelayedTransportMethod

The tier-6 relayed-transport (TURN-like) method — proxies ALL peer data through the relay. Only reached when every more-direct method (including the tier-5 hole punch) has failed.

ReservationRelayedTransport

The PRODUCTION RelayedTransport: opens the RLY-002 forwarding channel over the node’s LIVE persistent relay reservation (never a second socket), reusing the same RelayStatus handle the reservation loop publishes its outbound sink through. This is the tier-6 TURN fallback made real.

Traits

RelayedTransport

Abstraction over the relay data plane: open a stream to target_peer whose bytes are proxied THROUGH the relay (RLY-002). This is the tier-6 TURN-like fallback — distinct from the tier-5 HolePunchCoordinator, which only signals.