WebSocket: Don't instantiate a SytemRNG on every client request
WebSocket: Don't instantiate a SytemRNG on every client request

Previously, every call to Frame.writeFrame as a client would instantiate
a SystemRNG (which on Linux opens a FD) and a 4 bytes buffer that would
immediately be thrown away.

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