I was running some benchmarks with the apache-bench and the following error showed up:

[B72F3F80:B72F6DC0 WRN] Handling of connection failed: Remote hung up while operating on TCPConnection.
[B72F3F80:00000000 ERR] Task terminated with unhandled exception: object.Exception@/home/dev/apps/vibe.d/source/vibe/core/drivers/libevent2_tcp.d(470): Error reading data from socket. Remote hung up?

/tmp/.rdmd-1000/rdmd-app.d-680553F408B240E4B699E899B567B6C1/app(void vibe.core.core.CoreTask.run()+0x21) [0x81e9a31]
/tmp/.rdmd-1000/rdmd-app.d-680553F408B240E4B699E899B567B6C1/app(void core.thread.Fiber.run()+0x21) [0x8224de1]
/tmp/.rdmd-1000/rdmd-app.d-680553F408B240E4B699E899B567B6C1/app(fiber_entryPoint+0x4e) [0x8224d1e]
[(nil)]

I did this with 10 concurrent users and trying 100,000 requests. I can only tell you right now that I was interacting with a Redis database on all of these requests, so I don't know if that' why it failed or if it was due to something else. I would provide code, but it's work-related, so I can't publish it. However, when I get some time, I'll try to duplicate it with some different code. I just wanted to make you aware of this before I forgot.