Segfault - nil pointer dereference

[aldanor]

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x28 pc=0x7ed6b6]

goroutine 17231123 [running]:
ktbs.dev/mubeng/pkg/mubeng.(*Proxy).New(0xc0316e6f50, 0xc146b1c600)
        /root/mubeng/pkg/mubeng/mubeng.go:27 +0x156
ktbs.dev/mubeng/internal/server.(*Proxy).onRequest.func1(0xc146b1c600)
        /root/mubeng/internal/server/handler.go:63 +0x2cd
created by ktbs.dev/mubeng/internal/server.(*Proxy).onRequest
        /root/mubeng/internal/server/handler.go:44 +0x372

Unfortunately I'm not able to reproduce it directly but it already happened a few times (running on ubuntu, latest master version, go 1.20), after pushing a few hundred thousand requests through the proxy server at a rate of a few hundreds per second.