No response to initialize request

[walcht]

Issue:
The debug adapter doesn't respond to the following request:

Content-Length: 377\r\n\r\n{"type": "request", "seq": 1, "command": "initialize", "arguments": {"adapterID": "nvim-dap", "clientID": "neovim", "clientName": "neovim", "columnsStartAt1": true, "linesStartAt1": true, "locale": "en_US.UTF-8", "pathFormat": "path", "supportsProgressReporting": true, "supportsRunInTerminalRequest": true, "supportsStartDebuggingRequest": true, "supportsVariableType": true}}

Reason:
String.IndexOf(TWO_CRLF) returns -1 instead of the expected value 19
(related to: dotnet/runtime#43736)

Fix:
Using a verbatim string solves the issue

protected const string TWO_CRLF = @"\r\n\r\n";

built using dotnet version 9.0.108
ran using mono version Mono JIT compiler version 6.8.0.105
on:

Distributor ID: Ubuntu
Description:    Ubuntu 24.04.2 LTS
Release:        24.04
Codename:       noble