Allow multiple spinners

[neuecc]

Currently Spinner can not run multiple in multi-threading.

This PR stores CursorTop and lock Console operations.

Also I've found bug of !CanAcceptEscapeSequence's clear line code.

_lineLength = frame.Length + 1 + Text.Length; is not work for non-ascii character.
I've modified to _lineLength = Console.CursorLeft; after console out flushed.

[neuecc]

Sorry, after first open PR, I've changed implementation.
to allow other console writing, always render terminator and add Start(string terminator) overload.

Also added as a hack, using Console.s_syncObject for lock if can.

[mayuki]

Great! But unfortunately, it seems that the output is corrupted when running on CI or enabled = false state.

Expected:

Actual (Text will appear in unexpected places):

And, in the case of Linux terminal, it will not display correctly at the window buffer boundary.

2021-12-04.10-47-48.mp4

The window buffer (Console.BufferHeight) other boundary problem seems to exist on Windows as well.
For example, If you run Spinner after for (var i = 0; i < 10000; i++) { Console.WriteLine(i); }, an exception is thrown.

[neuecc]

@mayuki
thanks, I've fixed both and checked Windows/Linux, CI=1/none enviroments.

If reached window boundary, I've added check of position and subtract new line.

_cursorTop = Console.CursorTop;
Console.Write(terminator);
Console.Out.Flush();

// reaches window boundary
if (_cursorTop == Console.CursorTop)
{
    _cursorTop = Math.Max(_cursorTop - 1, 0);
    foreach (var item in s_runningSpinners)
    {
        item._cursorTop = Math.Max(item._cursorTop - 1, 0);
    }
}

-1 doesn't work when the usual Console.WriteLine is sandwiched in between, but it's still better than the previous version (which completely broke the behavior).

[mayuki]

-1 doesn't work when the usual Console.WriteLine is sandwiched in between, but it's still better than the previous version (which completely broke the behavior).

I would like to consider addressing that case in the future.