Drop a listener (e.g. when its GET stream is closed). Any in-flight
server->client request that was delivered on this listener is failed
immediately so its awaiter wakes with an McpException instead of hanging
for the full timeout. Acquires the delivery mutex so it cannot interleave
with an in-progress write or another list mutation.
Drop a listener (e.g. when its GET stream is closed). Any in-flight server->client request that was delivered on this listener is failed immediately so its awaiter wakes with an McpException instead of hanging for the full timeout. Acquires the delivery mutex so it cannot interleave with an in-progress write or another list mutation.