public static void main(String[] args) {
    for (int i = 0; i < 4; i++) {
      System.err.println();
      testMinHeap("quaternary", n -> LongMinHeap.newArrayHeap(n, Integer::compare));
      System.err.println(String.join("\t",
        "priorityqueue",
        Long.toString(testPriorityQueue(10).toMillis()),
        Long.toString(testPriorityQueue(100).toMillis()),
        Long.toString(testPriorityQueue(1_000).toMillis()),
        Long.toString(testPriorityQueue(10_000).toMillis())));
    }
  }
Performance tests for {@link LongMinHeap} implementations.

Times how long it takes to merge N sorted lists of random elements.
planetiler-benchmarks/src/main/java/com/onthegomap/planetiler/collection/BenchmarkKWayMerge.java