`DokanInstanceBuilder.Build` returns before file system is ready

[lostmsu]

Trying to access the new file system immediately after it is built fails with ERROR_INVALID_FUNCTION or ERROR_INVALID_PARAMETER (depending on type of access).

IMHO, Build by default should wait for the file system to be ready.

Workaround

const uint ERROR_INVALID_PARAMETER = 0x0057;
bool done = false;
while(!done) {
    try {
        mountDir.EnumerateFileSystemInfos().Any();
        done = true;
    } catch (IOException e)
        when (GetWin32Error(e.HResult) == ERROR_INVALID_PARAMETER) {
        await Task.Delay(TimeSpan.FromMilliseconds(25), cancel)
                  .ConfigureAwait(false);
    }
}

static uint GetWin32Error(int hResult)
    => unchecked((uint)hResult) & 0xFFFF;

See also dokan-dev/dokan-dotnet#356

[Liryna]

This might be due to DokanCreateFileSystem returning before DispatchDedicatedIoCallback worker threads (which fully enable the device when they first reach the kernel and register themselves).
We would need to add a logic that they signal they get there.

dokany/dokan/dokan.c

Lines 824 to 826 in 69e3d88

	QueueIoEvent(ioEvent, allowIpcBatching
	? DispatchBatchIoCallback
	: DispatchDedicatedIoCallback);

Moving to dokany repository since it is a native improvement.