1. Add sync.Mutex to ScoutConnCollected to eliminate data race between
Add()/MarkWrite() in readLoop and learn() iterating results.
Introduce Snapshot() for safe read access.
2. Increase bloom filter test size from 500 to 100000 to prevent
false negatives from random eviction in the stable bloom filter.
3. Use Require().NoError() in TestHTTPSRequest to prevent nil-pointer
panic on resp.Body.Close() when the request fails.
Fixes#425
Alexey Dolotov
9seconds