Assemble frames in OutgoingWebSocketMessage in a single buffer. Fixes #1791.
Assemble frames in OutgoingWebSocketMessage in a single buffer. Fixes #1791.

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