Fix segfault caused hash map iteration with concurrent remove. Fixes #1608.
Fix segfault caused hash map iteration with concurrent remove. Fixes #1608.

chalucha/vibe.d,etcimon/vibe.d,Geod24/vibe.d,DBankov/vibe.d,etcimon/vibe.d,rejectedsoftware/vibe.d,gedaiu/vibe.d