Clock jitter in hrtime.bigInt()

hrtime.js

function bench() {
    let samples = [];
    let start = process.hrtime.bigint();

    for (let i = 0; i < 100_000_000; i++) {
        let s = process.hrtime.bigint();

        let foo = JSON.parse('{ "a": 1, "b": 2, "c": 3, "d": 4 }');

        samples.push(process.hrtime.bigint() - s);
    }

    let total = process.hrtime.bigint() - start;
    let sampledAverage = samples.reduce((acc, entry) => acc + entry, BigInt(0));

    console.log(total/BigInt(100_000_000), "average")
    console.log("  vs");
    console.log(sampledAverage/BigInt(100_000_000), "sampled");
}

function benchEmpty() {
    let samples = [];
    let start = process.hrtime.bigint();

    for (let i = 0; i < 100_000_000; i++) {
        let s = process.hrtime.bigint();
        samples.push(process.hrtime.bigint() - s);
    }

    let total = process.hrtime.bigint() - start;
    let sampledAverage = samples.reduce((acc, entry) => acc + entry, BigInt(0));

    console.log(sampledAverage/BigInt(100_000_000), "back-to-back hrtime()")
    console.log(total/BigInt(100_000_000), "bookkeeping")
}

bench();
console.log("benchEmpty():")
benchEmpty();
bench();
console.log("benchEmpty():")
benchEmpty();
bench();
console.log("benchEmpty():")
benchEmpty();

/*
worst case from 3 runs.  best run was 1-2ns, 1st run 2-5ns
338n average
  vs
284n sampled
benchEmpty():
7n back-to-back hrtime()
93n bookkeeping
334n average
  vs
274n sampled
benchEmpty():
12n back-to-back hrtime()
95n bookkeeping
340n average
  vs
280n sampled
benchEmpty():
10n back-to-back hrtime()
96n bookkeeping
*/