private static void testMinHeap(String name, IntFunction<LongMinHeap> constructor) {
    System.err.println(String.join("\t",
      name,
      Long.toString(testUpdates(10, constructor).toMillis()),
      Long.toString(testUpdates(100, constructor).toMillis()),
      Long.toString(testUpdates(1_000, constructor).toMillis()),
      Long.toString(testUpdates(10_000, constructor).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