TUN-4597: Add a QUIC server skeleton

- Added a QUIC server to accept streams
- Unit test for this server also tests ALPN
- Temporary echo capability for HTTP ConnectionType

vendor/golang.org/x/sys/unix/zsyscall_linux.go

@@ -1,5 +1,6 @@
 // Code generated by mkmerge.go; DO NOT EDIT.
 
+//go:build linux
 // +build linux
 
 package unix
@@ -531,6 +532,16 @@ func Close(fd int) (err error) {
 
 // THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
 
+func CloseRange(first uint, last uint, flags uint) (err error) {
+	_, _, e1 := Syscall(SYS_CLOSE_RANGE, uintptr(first), uintptr(last), uintptr(flags))
+	if e1 != 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
+// THIS FILE IS GENERATED BY THE COMMAND AT THE TOP; DO NOT EDIT
+
 func CopyFileRange(rfd int, roff *int64, wfd int, woff *int64, len int, flags int) (n int, err error) {
 	r0, _, e1 := Syscall6(SYS_COPY_FILE_RANGE, uintptr(rfd), uintptr(unsafe.Pointer(roff)), uintptr(wfd), uintptr(unsafe.Pointer(woff)), uintptr(len), uintptr(flags))
 	n = int(r0)