try {
                        ((Destroyable) masterKey).destroy();
                    } catch (DestroyFailedException e) {
                        // Log but continue - not all JVM implementations support destroying SecretKey
                        log.debug("SecretKey destroy not fully supported: {}", e.getMessage());
                        failedToDestroy = true;

## An app with callbacks { #an-app-with-callbacks }

Let's see all this with an example.

Imagine you develop an app that allows creating invoices.

These invoices will have an `id`, `title` (optional), `customer`, and `total`.

* Security - HTTPS
* Running on startup
* Restarts
* **Replication (the number of processes running)**
* Memory
* Previous steps before starting

Up to this point, with all the tutorials in the docs, you have probably been running a **server program**, for example, using the `fastapi` command, that runs Uvicorn, running a **single process**.

	if runtime.GOOS == "linux" {
		// Honor cgroup limits if set.
		limit := cgroupMemLimit()
		if limit > 0 {
			// A valid value is found, return its 90%
			available = (limit * 9) / 10
			return
		}
	} // for all other platforms limits are based on virtual memory.

	memStats, err := mem.VirtualMemory()
	if err != nil {
		return
	}

	// A valid value is available return its 90%

# Copyright 2023 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,

    testConcurrentLoading(CacheBuilder.newBuilder().expireAfterWrite(10, SECONDS));
  }

  /**
   * On a successful concurrent computation, only one thread does the work, but all the threads get
   * the same result.
   */
  private static void testConcurrentLoadingDefault(CacheBuilder<Object, Object> builder)
      throws InterruptedException {

    int count = 10;

    }

    private static void createJob() {
        final Map<String, Object> requestBody = new HashMap<>();
        requestBody.put("name", NAME_PREFIX + "Scheduler");
        requestBody.put("target", "all");
        requestBody.put("script_type", "groovy");
        requestBody.put("sort_order", 0);
        requestBody.put("crawler", true);
        requestBody.put("job_logging", true);

    .build();
OkHttpClient client = new OkHttpClient.Builder()
    .sslSocketFactory(clientCertificates.sslSocketFactory(), clientCertificates.trustManager())
    .build();

// Connect 'em all together. Certificates are exchanged in the handshake.
Call call = client.newCall(new Request.Builder()
    .url(server.url("/"))
    .build());
Response response = call.execute();

          try {
            if (timer != null) {
              long overDelayMs = Math.abs(timer.getDelay(MILLISECONDS));
              if (overDelayMs > 10) { // Not all timing drift is worth reporting
                message += " (timeout delayed by " + overDelayMs + " ms after scheduled time)";
              }
            }
            message += ": " + delegate;
          } finally {

   *         .addNode(REYKJAVIK)
   *         .build();
   * }
   *
   * <p>Builder instances can be reused; it is safe to call {@link #build} multiple times to build
   * multiple graphs in series. Each new graph contains all the elements of the ones created before
   * it.
   *
   * @since 28.0
   */
  public static class Builder<N, V> {

    private final MutableValueGraph<N, V> mutableValueGraph;