BREAKING(io): remove BufReader

[iuioiua]

What's changed

BufReader has been removed from @std/io.

Motivation

This change was made to help push users towards using the Streams API and @std/streams, and make design decisions about which APIs easier.

Migration guide

To migrate, use Buffer from @std/streams instead. If you have any use cases which lack a clear means of migration, open an issue.

Before:

import { Buffer, BufReader } from "@std/io";
import { assertEquals } from "@std/assert/equals";

const encoder = new TextEncoder();
const decoder = new TextDecoder();

const reader = new BufReader(new Buffer(encoder.encode("Hello, world!")));
const buffer = new Uint8Array(11);
await reader.read(buffer);
const result = decoder.decode(buffer);

assertEquals(result, "Hello, world!");

After:

import { Buffer } from "@std/streams/buffer";
import { toText } from "@std/streams/to-text";
import { assertEquals } from "@std/assert";

const encoder = new TextEncoder();

const buffer = new Buffer(encoder.encode("Hello, world!"));
const result = await toText(buffer.readable);

assertEquals(result, "Hello, world!");

Related

Towards #5989

[kt3k]

LGTM