Method timeTest

concurrent/Summing.java:10–20

(String id, long checkValue,
    LongSupplier operation)

public class Summing {
  static void timeTest(String id, long checkValue,
    LongSupplier operation) {
    System.out.print(id + ": ");
    Timer timer = new Timer();
    long result = operation.getAsLong();
    if(result == checkValue)
      System.out.println(timer.duration() + "ms");
    else
      System.out.format("result: %d%ncheckValue: %d%n",
        result, checkValue);
  }
  public static final int SZ = 100_000_000;
  // This even works:
  // public static final int SZ = 1_000_000_000;