///

## Returning a custom `Response`

The example above shows all the parts you need, but it's not very useful yet, as you could have just returned the `item` directly, and **FastAPI** would put it in a `JSONResponse` for you, converting it to a `dict`, etc. All that by default.

Now, let's see how you could use that to return a custom response.

// operations, such as bitrot verification or data usage scanning.
// Every 10 seconds a space character is sent.
// keepHTTPReqResponseAlive will wait for the returned body to be read before starting the ticker.
// The returned function should always be called to release resources.
// An optional error can be sent which will be picked as text only error,
// without its original type by the receiver.

public abstract class ImmutableMultimap<K, V> extends BaseImmutableMultimap<K, V>
    implements Serializable {

  /**
   * Returns an empty multimap.
   *
   * <p><b>Performance note:</b> the instance returned is a singleton.
   */
  public static <K, V> ImmutableMultimap<K, V> of() {
    return ImmutableListMultimap.of();
  }

  /** Returns an immutable multimap containing a single entry. */

    throwFirst(nullErrors);
    return null;
  }

  /**
   * Instantiates using {@code factory}. If {@code factory} is annotated nullable and returns null,
   * null will be returned.
   *
   * @throws ParameterNotInstantiableException if the static methods cannot be invoked because the
   *     default value of a parameter cannot be determined.

import javax.annotation.CheckForNull;

/**
 * A {@link MapIteratorCache} that adds additional caching. In addition to the caching provided by
 * {@link MapIteratorCache}, this structure caches values for the two most recently retrieved keys.
 *
 * @author James Sexton
 */
@ElementTypesAreNonnullByDefault
final class MapRetrievalCache<K, V> extends MapIteratorCache<K, V> {
  // See the note about volatile in the superclass.

   *
   * <pre>{@code
   * public int hashCode() {
   *   return Objects.hashCode(getX(), getY(), getZ());
   * }
   * }</pre>
   *
   * <p><b>Warning:</b> When a single object is supplied, the returned hash code does not equal the
   * hash code of that object.
   *
   * <p><b>Note:</b> this method is now unnecessary and should be treated as deprecated; use {@link
   * java.util.Objects#hash} instead.
   */

	if ct.NameValue.Valid {
		return ct.NameValue.String
	}
	return ct.SQLColumnType.Name()
}

// DatabaseTypeName returns the database system name of the column type. If an empty
// string is returned, then the driver type name is not supported.
// Consult your driver documentation for a list of driver data types. Length specifiers
// are not included.
// Common type names include "VARCHAR", "TEXT", "NVARCHAR", "DECIMAL", "BOOL",

   * and {@code toIndex}, exclusive. (If {@code fromIndex} and {@code toIndex} are equal, the empty
   * immutable list is returned.)
   *
   * <p><b>Note:</b> in almost all circumstances, the returned {@link ImmutableList} retains a
   * strong reference to {@code this}, which may prevent the original list from being garbage

  }

  private fun WebSocketExtensions.isValid(): Boolean {
    // If the server returned parameters we don't understand, fail the web socket.
    if (unknownValues) return false

    // If the server returned a value for client_max_window_bits, fail the web socket.
    if (clientMaxWindowBits != null) return false

    // If the server returned an illegal server_max_window_bits, fail the web socket.

    // initial map.get()
    when(backingMap.get(KEY)).thenReturn(null);
    // since get returned null, try a putIfAbsent; that fails due to a simulated race
    when(backingMap.putIfAbsent(eq(KEY), isA(AtomicInteger.class))).thenReturn(existingZero);
    // since the putIfAbsent returned a zero, we'll try to replace...
    when(backingMap.replace(eq(KEY), eq(existingZero), isA(AtomicInteger.class))).thenReturn(false);