Давайте рассмотрим это на примере.

Представьте, что вы разрабатываете приложение, позволяющее создавать счета.

Эти счета будут иметь `id`, `title` (необязательный), `customer` и `total`.

Пользователь вашего API (внешний разработчик) создаст счет в вашем API с помощью POST-запроса.

Затем ваш API (предположим) сделает следующее:

* Отправит счет клиенту внешнего разработчика.
* Получит оплату.

// TODO this will be the class that people get in IDEs to modify

/**
 * MavenExecutionPlan
 */
public class MavenExecutionPlan implements Iterable<ExecutionPlanItem> {

    /*
      At the moment, this class is totally immutable, and this is in line with thoughts about the
      pre-calculated execution plan that stays the same during the execution.

      If deciding to add mutable state to this class, it should be at least considered to

    assertEquals("abcd", mediaType.parameter("BOUNDARY"))
  }

  @Test fun testMultipleParameters() {
    val mediaType = parse("Message/Partial; number=2; total=3; id=\"oc=******@****.***\"")
    assertEquals("2", mediaType.parameter("number"))
    assertEquals("3", mediaType.parameter("total"))
    assertEquals("oc=******@****.***", mediaType.parameter("id"))
    assertNull(mediaType.parameter("foo"))
  }

...
11:55:40 I/XmlResultReporter: XML test result file generated at /Users/myusername/workspace/okhttp/regression-test/build/outputs/regression-results/connected/TEST-pixel3a-Q(AVD) - 10-android-test-.xml. Total tests 13, passed 11, assumption_failure 1, ignored 1,
...
BUILD SUCCESSFUL in 1m 30s
63 actionable tasks: 61 executed, 2 up-to-date

```

        assertEquals(0, (dst[5] << 8) | (dst[4] & 0xFF));
    }

    @Test
    void testWriteDataWireFormat() {
        // Given
        // writeInt8 writes 8 bytes but needs to access dst[dstIndex+7]
        // Total bytes written: 8+8+8+8+2+6=40
        // But writeInt8 at position 34 needs to access position 34+7=41
        // So we need at least 42 bytes in the array
        byte[] dst = new byte[42];

        // When

 *             are incremented, and the total loading time, in nanoseconds, is added to {@code
 *             totalLoadTime}.
 *         <li>When an exception is thrown while loading an entry, {@code missCount} and {@code
 *             loadExceptionCount} are incremented, and the total loading time, in nanoseconds, is
 *             added to {@code totalLoadTime}.

 *             are incremented, and the total loading time, in nanoseconds, is added to {@code
 *             totalLoadTime}.
 *         <li>When an exception is thrown while loading an entry, {@code missCount} and {@code
 *             loadExceptionCount} are incremented, and the total loading time, in nanoseconds, is
 *             added to {@code totalLoadTime}.

    for (int i = 0; i < threads; i++) {
      futures.add(threadPool.submit(task));
    }
    long total = 0;
    for (Future<Long> future : futures) {
      total += future.get();
    }
    return total;
  }

  private long runAddSingleThread(int reps) {
    Random random = new Random();
    int nKeys = keys.size();
    long blah = 0;

	notificationEventsErrorsTotalMD     = NewCounterMD(notificationEventsErrorsTotal, "Events that were failed to be sent to the targets")
	notificationEventsSentTotalMD       = NewCounterMD(notificationEventsSentTotal, "Total number of events sent to the targets")
	notificationEventsSkippedTotalMD    = NewCounterMD(notificationEventsSkippedTotal, "Events that were skipped to be sent to the targets due to the in-memory queue being full")
)

     * Calculate success rate
     *
     * @return success rate (0.0 to 1.0)
     */
    private double getSuccessRate() {
        long total = totalCalls.get();
        if (total == 0) {
            return 1.0;
        }
        return (double) totalSuccesses.get() / total;
    }

    /**
     * Check if circuit breaker allows requests
     *
     * @return true if requests are allowed
     */