AM-1 (rank-space):ActorMeshRef uses its CastDomainRef as
the source of truth for actor addresses. The cast domain stores
members in the same dense rank order as the mesh Region, so a
rank can be materialized by indexing the cast-domain member map
directly; the reference does not need to retain the ProcMeshRef
that created it.
AM-2 (slice materialization):RankedSliceable::sliced has no
caller context, so it carries only a raw cast-domain descriptor. The first
cast through that ref materializes the descriptor with the caller context
before sending the cast message, sequencing setup and delivery on the same
sender stream.
Liveness watchdog for the supervision stream. If no
supervision message (healthy or unhealthy) is observed within
this duration, the controller is assumed to be unreachable and
the mesh is treated as unhealthy. This timeout is about
detecting silence, not slow messages.
This value must be > poll frequency + get actor state timeout + get proc state timeout
or else it is possible to declare the controller dead before it could
feasibly have received a healthy reply.