FakeChannelSeam
A Seam view returned by FakeRoom.channel.
peersreflects the admitted roster (+ self) via _rosterPeers.incomingis driven by test-driver deliver calls, buffered via a bounded Spool (policy from FakeRoom.channelPolicy).broadcast/sendTodelegate to FakeRoom.broadcast/sendTo with raw payloads (no channel framing added — the Fake is not a protocol layer).stateforwards _seamState.closeis a no-op — the FakeRoom owns the lifecycle.