A handler takes an event by returning and asks for it again by throwing;
any mesh/event answer but an error is taken. Written down in the README
where event handling is, with what follows for a handler: throw only when
the work was not done, and be safe to run twice.
Both SDKs added the handler before asking the runtime and kept it when the
runtime refused, so a module that asks again until it is taken (every Go
consumer does) ran its handler once per attempt for every event. A refused
subscribe now removes its handler; one the Go runtime did not answer in
time is kept, since the runtime may have bound it.
Subscribe(pattern, handler) asks the runtime for the module's events and answers each mesh/event
only after the matching handlers returned nil, so the runtime acknowledges it on the bus then and
not before; Ask(key, body) calls a tool as the module. Topic matching is the TypeScript SDK's.
What the TypeScript SDK's stdio loop does, in Go: an empty name serves as MESH_SERVED_MODULE; each
call runs beside the loop so a tool waiting on the runtime does not deadlock it; Emit asks the
runtime (mesh/publish) with the same envelope and headers. README says how to install it and how
releases are tagged.
jochen