## Um aplicativo com callbacks

Vamos ver tudo isso com um exemplo.

Imagine que você tem um aplicativo que permite criar faturas.

Essas faturas terão um `id`, `title` (opcional), `customer` e `total`.

O usuário da sua API (um desenvolvedor externo) criará uma fatura em sua API com uma solicitação POST.

Então sua API irá (vamos imaginar):

 * the License.
 */

/**
 * Concurrency utilities.
 *
 * <p>Commonly used types include {@link ClosingFuture}, {@link ListenableFuture}, and {@link
 * Service}.
 *
 * <p>Commonly used utilities include {@link Futures}, {@link MoreExecutors}, {@link
 * ThreadFactoryBuilder}, and {@link Uninterruptibles}.
 *
 * <p>This package is a part of the open-source <a href="https://github.com/google/guava">Guava</a>
 * library.
 */

- A working knowledge of AWS S3 API behaviors and corner cases.

## Pre-requisite for backporting any fixes

Fixes that are allowed a backport must satisfy any of the following criteria's:

- A fix must not be a feature, for example.

```
commit faf013ec84051b92ae0f420a658b8d35bb7bb000
Author: Klaus Post <******@****.***>
Date:   Thu Nov 18 12:15:22 2021 -0800

    Improve performance on multiple versions (#13573)
```

import jcifs.spnego.NegTokenTarg;
import jcifs.spnego.SpnegoException;
import jcifs.spnego.SpnegoToken;
import jcifs.util.Hexdump;


/**
 * This class used to wrap a {@link SSPContext} to provide SPNEGO feature.
 * 
 * @author Shun
 *
 */
class SpnegoContext implements SSPContext {

    private static final Logger log = LoggerFactory.getLogger(SpnegoContext.class);

import com.google.common.util.concurrent.testing.MockFutureListener;
import java.util.concurrent.TimeoutException;
import junit.framework.TestCase;

/**
 * Unit tests for any listenable future that chains other listenable futures. Unit tests need only
 * override buildChainingFuture and getSuccessfulResult, but they can add custom tests as needed.
 *
 * @author Nishant Thakkar
 */

    }

    override fun setName(name: String?) {
        throw UnsupportedOperationException()
    }

    override fun getDescription(): String = "Reports incorrect usages of integration test fixtures"

    override fun getAstVisitorClass(): Class<*> = IntegrationTestFixtureVisitor::class.java
}


class IntegrationTestFixtureVisitor : AbstractAstVisitor() {

    /**

  * This puts a much tighter budget on CPU, memory, latency, and throughput requirements than traditional Istio sidecars.

Ztunnel was not designed to be a feature-rich data plane.
Quite the opposite - an *aggressively* small feature set is the key feature that makes ztunnel viable.
It very intentionally does not offer L7 (HTTP) functionality, for instance, which would likely violate some of the goals above, without contributing to them.

  @Throws(IOException::class)
  override fun writeTo(sink: BufferedSink) {
    writeOrCountBytes(sink, false)
  }

  /**
   * Either writes this request to [sink] or measures its content length. We have one method
   * do double-duty to make sure the counting and content are consistent, particularly when it comes
   * to awkward operations like measuring the encoded length of header strings, or the

		TLSHandshakeTimeout:   15 * time.Second,
		ExpectContinueTimeout: 15 * time.Second,
		// Go net/http automatically unzip if content-type is
		// gzip disable this feature, as we are always interested
		// in raw stream.
		DisableCompression: true,
	}

	return &ReconnectRESTClient{
		u:    u,
		rest: rest.NewClient(u, tr, nil),
	}
}

 * limitations under the License.
 */

package com.google.common.util.concurrent;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.Futures.getDone;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;
import static com.google.common.util.concurrent.ReflectionFreeAssertThrows.assertThrows;