chore(log): rework std/log to work without deprecated Deno.Writer

[syhol]

Attempting to solve #3907

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

Previous attempt of #3969 was trying to use std/streams/buffer.ts and the streams API, but moving to async flushes resulted in potentially lost logs.

Now just solving with a Uint8Array and a ArrayBuffer and a number pointer.

[syhol]

Sure, TS private keyword or JS hash prefix?

[iuioiua]

Hash prefix please 🙂

[syhol]

All suggestions applied 🙏 ready for another review 🎉

[iuioiua]

Great work! Thank you for this.

[dvv]

Hi!

With this attempt to log circa 4096 octets message just dumps the process.

import { RotatingFileHandler } from "https://deno.land/[email protected]/log/mod.ts"

const logger = new RotatingFileHandler(
  "DEBUG",
  {
    filename: "/tmp/123",
    maxBytes: 4000000,
    maxBackupCount: 10,
  },
)
logger.log("x".repeat(4096))

error: Uncaught (in promise) RangeError: offset is out of bounds
    this._buf.set(bytes, this._pointer);
              ^
    at Uint8Array.set (<anonymous>)
    at RotatingFileHandler.log (https://deno.land/[email protected]/log/file_handler.ts:79:15)
    at RotatingFileHandler.log (https://deno.land/[email protected]/log/rotating_file_handler.ts:106:11)