Injector.java:391 caught only RuntimeException around the herdr send seam. PR #543
(fleetd #538) widened StatusPoller's per-target catch to Throwable so the polling
loop now survives an Error there, which means it comes back round — and Injector's
narrower catch let the poisoned message stay QUEUED (the loop peeks, not polls),
so the next round re-sent the same text into the member's pane.
Widen the catch to Throwable, matching #543 one layer down. sendError's declared
type widens from RuntimeException to Throwable to keep compiling; its only consumer
(CompletableFuture.completeExceptionally(Throwable)) already accepts that type, so
no other caller-visible behavior changes. The ordinary HerdrException/RuntimeException
path is unchanged.
Adds three tests: an Error at the send seam is dropped and marked NOT_DELIVERED, a
second onStatus round does not re-send it, and a HerdrException control proves the
ordinary path is untouched.
Dai Ha