perf(codec): avoid re-construct when concat bytes

[homura]

Resolve #374, the concat is used by every molecule layout and the current implementation is low performance.

This PR refactors concat via re-alloc a new Uint8Array and the benchmark has an improvement of about 100x

concat#re-construct x 21.36 ops/sec ±1.44% (40 runs sampled)
concat#re-alloc x 2,525 ops/sec ±1.73% (90 runs sampled)

benchmark.js

import Benchmark from "benchmark";
import { concat, concatViaReconstruct } from "@ckb-lumos/codec/lib/bytes";
import { randomBytes } from "crypto";

// export function concatViaReconstruct(...bytesLikes: BytesLike[]): Uint8Array {
//   return Uint8Array.from(
//     bytesLikes.flatMap((bytes) => Array.from(bytify(bytes)))
//   );
// }
//
// export function concat(...bytesLikes: BytesLike[]): Uint8Array {
//   const unmerged = bytesLikes.map(bytify);
//   const totalSize = unmerged.reduce((size, item) => size + item.length, 0);
//
//   const merged = new Uint8Array(totalSize);
//
//   let offset = 0;
//   unmerged.forEach((item) => {
//     merged.set(item, offset);
//     offset += item.length;
//   });
//
//   return merged;
// }

const bytesArr = Array.from({ length: 1000 }).map(() =>
  randomBytes(Math.ceil(1000 * Math.random()))
);

const suite = new Benchmark.Suite();

suite
  .add("concat#re-construct", () => {
    return concatViaReconstruct(...bytesArr);
  })
  .add("concat#re-alloc", () => {
    return concat(...bytesArr);
  })
  .on("cycle", function (event: any) {
    console.log(String(event.target));
  })
  .run();

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[codecov]

Codecov Report

Merging #375 (9c4cbf0) into develop (d91a96f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff            @@
##           develop     #375   +/-   ##
========================================
  Coverage    82.24%   82.25%           
========================================
  Files           81       81           
  Lines        17659    17668    +9     
  Branches      1695     1696    +1     
========================================
+ Hits         14524    14533    +9     
  Misses        3112     3112           
  Partials        23       23           

Impacted Files	Coverage Δ
packages/codec/src/bytes.ts	98.70% <100.00%> (+0.17%)	⬆️

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[zhangyouxin]

LGTM