The start composed every kept composition of every module on every node, each a
whole node composed in memory under the node's lock: 10 to 50 minutes at a
start, holding take-ins back. Now the writes of mesh-config_resolved are read
from the durable consumer mesh-controller-config-follow, acknowledged once the
change is composed, so a restart composes again only what was written since
the last change handled, and a first start nothing it did not hear. The node's
lock is taken for each write alone. A consumer that cannot be made or read
raises config-not-followed and is tried again a minute later, cleared once it
reads. The controller's account is granted that consumer's acknowledgements
where mesh-config serves, as its verb is.
Research 072: milestone 2, the composer reacting to the change of an input.