```
https://yourapi.com/invoices/?callback_url=https://www.external.org/events
```

con un JSON body de:

```JSON
{
    "id": "2expen51ve",
    "customer": "Mr. Richie Rich",
    "total": "9999"
}
```

luego *tu API* procesará la factura y, en algún momento después, enviará un request de callback al `callback_url` (la *API externa*):

```

import java.util.Collection;
import java.util.Set;
import junit.framework.Test;
import junit.framework.TestCase;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullUnmarked;

/**
 * @author Gregory Kick
 */
@GwtCompatible
@NullUnmarked
public class ContiguousSetTest extends TestCase {
  private static final DiscreteDomain<Integer> NOT_EQUAL_TO_INTEGERS =
      new DiscreteDomain<Integer>() {
        @Override

				"application/vnd.commonspace",
				"application/vnd.contact.cmsg",
				"application/vnd.cosmocaller",
				"application/vnd.crick.clicker",
				"application/vnd.crick.clicker.keyboard",
				"application/vnd.crick.clicker.palette",
				"application/vnd.crick.clicker.template",
				"application/vnd.crick.clicker.wordbank",
				"application/vnd.criticaltools.wbs+xml",
				"application/vnd.ctc-posml",
				"application/vnd.ctct.ws+xml",

import junit.framework.Test;
import junit.framework.TestSuite;
import org.jspecify.annotations.NullMarked;

/**
 * Unit test for {@link ImmutableSet}.
 *
 * @author Kevin Bourrillion
 * @author Jared Levy
 * @author Nick Kralevich
 */
@GwtCompatible
@NullMarked
public class ImmutableSetTest extends AbstractImmutableSetTest {

  @J2ktIncompatible
  @GwtIncompatible // suite
  @AndroidIncompatible // test-suite builders

   * response body. Call `body.source().request(1024 * 1024)` to block until either that's done, or
   * 1 MiB of response data is loaded into memory. (You could use any size here, though large values
   * risk exhausting memory.)
   *
   * This returns an empty value if the trailers are available, but have no data.
   *
   * It is not safe to call this concurrently with code that is processing the response body.
   *

 * at {@link ImmutableCollection}.
 *
 * <p>See the Guava User Guide article on <a href=
 * "https://github.com/google/guava/wiki/ImmutableCollectionsExplained">immutable collections</a>.
 *
 * @author Gregory Kick
 * @since 11.0
 */
@GwtCompatible
public abstract class ImmutableTable<R, C, V> extends AbstractTable<R, C, V>
    implements Serializable {

  /**

     */
    public Date getLogoffTime() {
        return this.logoffTime;
    }

    /**
     * Returns the time when the user's session will be forcibly terminated.
     * @return the kick off timestamp
     */
    public Date getKickOffTime() {
        return this.kickOffTime;
    }

    /**
     * Returns the time when the user's password was last changed.

   * For now, we continue using it to clean up under older JDKs.
   *
   * Our usages should at least be *relatively* safe: Typically, threads started by a test are dying
   * at the end of the test, so there is no object state put at risk by stopping the threads
   * abruptly. In other cases, a test may put a thread into an uninterruptible operation
   * intentionally, so there is no other way to clean up these threads. (The better solution,

        Class<?> rawPropertyType = paramType.getRawType();

        if (valueType != null && rawPropertyType.isAssignableFrom(valueType)) {
            rawPropertyType = valueType; // pick more specific type
        }

        return convertProperty(beanType, rawPropertyType, paramType.getType(), configuration);
    }

    /**
     * Convert property using appropriate converter.
     */

         */
        public int hunds;
        /**
         * The time zone offset from UTC in minutes.
         */
        public int timezone;
        /**
         * The time interval for each tick of the clock in 0.0001 seconds.
         */
        public int tinterval;
        /**
         * The current day of the month (1-31).
         */
        public int day;
        /**