sendTo
Send bytes to one specific admitted member.
Reports an undeliverable first hop, unlike broadcast: an addressed send names a peer, so failing to reach it is information the caller asked for. Wrap in runCatchingCancellable for best-effort semantics.
The reserved leading bytes documented on broadcast apply here identically — the far end classifies every inbound frame the same way regardless of how it was addressed.
Throws
if bytes exceeds maxPayloadBytes. Raised before the frame is built, so the caller gets the budget it should have respected rather than the fabric's own frame error.
if the hop this member must perform cannot be made. Where the frame is relayed via a host, the peer named is that host — the hop that failed — rather than peer, to which this member has no direct route. Delivery beyond the first hop is not reported either way.