@hashes is never cleaned

[jaroszan]

@Hashes (endpoint.rb) only grows and items are never removed.

Perhaps it could be cleaned inside mark_call_dead function in the similar way as @dead_calls, however is it thread-safe? Should it be wrapped inside mutex synchronize block?

Or may be clean up should happen in one place, say separate thread which would (still with mutex) remove expired records from both @dead_calls and @Hashes? In that case should @Hashes be Hash as well?