suggestion: rework `std/log` to use Streams API

[iuioiua]

std/log is the last of the sub-modules that uses the deprecated Writer (i.e. Deno.Writer) interface. It should use WritableStream instead.

Related:

• chore: deprecate Deno.Reader, Deno.ReaderSync, Deno.Writer, Deno.WriterSync and Deno.Closer deno#21465
• tracking: Deno streams to web streams conversion #1986

[syhol]

I'm having a go at this.

It looks like moving to the Streams API causes some of the handler methods to become async, this might introduce complexities around what happens if a log comes in mid flush as operations are no longer atomic, especially so for the RotatingFileHandler.

Would you mind if I submit a WIP PR to see if I'm on the right track? I might need to implement a queue to buffer the buffer.

[iuioiua]

That's great to hear! I've looked at your PR, and it seems like you're on the right track for now. Please let us know if you have any questions.

[iuioiua]

An alternative was provided in #4021 that used Deno.FsFile.writeSync() and removed the dependency on Deno.Writer. Thank you for solving this, @syhol!