Replace assertion from BotanTLSStream with a warning message. Fixes #1918.
Replace assertion from BotanTLSStream with a warning message. Fixes #1918.

See #1958.

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