perf: use crypto.hash when available

[pimterry]

crypto.hash is very significantly faster than the createHash+update+digest dance for small content, and it's now available in all supported Node versions. This PR optimistically uses it when available (20.12.0+) if the body is relatively small (<100KB).

Direct benchmark for the two APIs below, on my machine this makes hashing in etag up to 3.2x faster for small strings, and 2.4x faster for small buffers.

Benchmark:

// Compares the two SHA-1 implementations. No dependencies: node bench.js
var crypto = require('crypto');

function before (entity) {
  return crypto.createHash('sha1').update(entity, 'utf8').digest('base64');
}

function after (entity) {
  return crypto.hash('sha1', entity, 'base64');
}

function time (fn, entity, n) {
  for (var i = 0; i < n; i++) fn(entity); // warm up
  var start = process.hrtime.bigint();
  for (var j = 0; j < n; j++) fn(entity);
  return Number(process.hrtime.bigint() - start) / n;
}

function report (label, entity, n) {
  var was = time(before, entity, n);
  var now = time(after, entity, n);
  console.log(label + ': createHash ' + was.toFixed(0) + 'ns, crypto.hash ' +
    now.toFixed(0) + 'ns, ' + (was / now).toFixed(2) + 'x faster');
}

console.log(process.version);

[10, 100, 1000, 10 * 1024, 100 * 1024, 1_000 * 1024].forEach(function (size) {
  var body = crypto.randomBytes(size);
  var n = 10000;

  report(size + 'B buffer', body, n);
  report(size + 'B string', body.toString('latin1'), n);
})

Results on my machine with latest Node below. Significantly faster up to 10KB, then roughly equal. I tested a bit further (slowly) and it drops off, and docs say >5MB is likely slower. I've put the limit at 100KB here.

➜ node test.js
v26.8.1
10B buffer: createHash 859ns, crypto.hash 353ns, 2.43x faster
10B string: createHash 647ns, crypto.hash 199ns, 3.25x faster
100B buffer: createHash 557ns, crypto.hash 245ns, 2.27x faster
100B string: createHash 687ns, crypto.hash 264ns, 2.60x faster
1000B buffer: createHash 922ns, crypto.hash 597ns, 1.54x faster
1000B string: createHash 1361ns, crypto.hash 953ns, 1.43x faster
10240B buffer: createHash 4926ns, crypto.hash 4465ns, 1.10x faster
10240B string: createHash 7489ns, crypto.hash 7137ns, 1.05x faster
102400B buffer: createHash 42909ns, crypto.hash 42591ns, 1.01x faster
102400B string: createHash 69641ns, crypto.hash 68860ns, 1.01x faster
1024000B buffer: createHash 427863ns, crypto.hash 428869ns, 1.00x faster
1024000B string: createHash 702380ns, crypto.hash 706478ns, 0.99x faster