As in other similar drivers (jsonlog, local), use a set
(i.e. `map[whatever]struct{}`), making the code simpler.
While at it, make sure we remove the reader from the set
after calling `ProducerGone()` on it.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
(cherry picked from commit b2b169f13f681cd0d591ccb06d6cfff97933db77)
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Upstream-commit: fe85c72a2eac4cbf249d2c4c754684bb447eefdd
Component: engine