* the underlying collection.
   *
   * <p>The returned collection isn't threadsafe or serializable, even if {@code unfiltered} is.
   *
   * <p>Many of the filtered collection's methods, such as {@code size()}, iterate across every
   * element in the underlying collection and determine which elements satisfy the filter. When a
   * live view is <i>not</i> needed, it may be faster to copy {@code Iterables.filter(unfiltered,
   * predicate)} and use the copy.

    assertThat(server.receivedPingCount()).isEqualTo(0)
    assertThat(server.receivedPongCount()).isEqualTo(0)
    closeWebSockets(webSocket, server)
  }

  /**
   * Configure the websocket to send pings every 500 ms. Artificially prevent the server from
   * responding to pings. The client should give up when attempting to send its 2nd ping, at about
   * 1000 ms.
   */
  @Test
  fun unacknowledgedPingFailsConnection() {

 * than {@code size()}. Furthermore, this structure only depends on a fixed number of arrays; {@code
 * add(x)} operations <i>do not</i> create objects for the garbage collector to deal with, and for
 * every element added, the garbage collector will have to traverse {@code 1.5} references on
 * average, in the marking phase, not {@code 5.0} as in {@code java.util.HashSet}.
 *

      }
    }
  }

  @GwtIncompatible // DoubleMath.roundToLong(double, RoundingMode)
  public void testRoundExactIntegralDoubleToLong() {
    for (double d : INTEGRAL_DOUBLE_CANDIDATES) {
      // every mode except UNNECESSARY
      BigDecimal expected = new BigDecimal(d).setScale(0, UNNECESSARY);
      boolean isInBounds =
          expected.compareTo(MAX_LONG_AS_BIG_DECIMAL) <= 0

         *
         * We carry out this computation in modular arithmetic. Since times2ToThe32Mod accepts any
         * unsigned long, we don't have to do a mod on every operation, only when intermediate
         * results can exceed 2^63.
         */
        long result = times2ToThe32Mod(aHi * bHi /* < 2^62 */, m); // < m < 2^63

behalf of any Contributor. You must make it absolutely clear that any
such warranty, support, indemnity, or liability obligation is offered by
You alone, and You hereby agree to indemnify every Contributor for any
liability incurred by such Contributor as a result of warranty, support,
indemnity or liability terms You offer. You may include additional
disclaimers of warranty and limitations of liability specific to any

   *
   * <ul>
   *   <li>A and B have equal {@link #isDirected() directedness}.
   *   <li>A and B have equal {@link #nodes() node sets}.
   *   <li>A and B have equal {@link #edges() edge sets}.
   *   <li>Every edge in A and B connects the same nodes in the same direction (if any).
   * </ul>
   *
   * <p>Network properties besides {@link #isDirected() directedness} do <b>not</b> affect equality.

  - `priority_level_seat_count_watermarks` is removed.
  - `priority_level_request_count_samples` is replaced with `priority_level_request_utilization`, which samples every nanosecond rather than every millisecond; the old metric conveyed utilization despite its name.

That should make more sense now. ✨

All that is what powers FastAPI (through Starlette) and what makes it have such an impressive performance.

## Very Technical Details { #very-technical-details }

/// warning

You can probably skip this.

These are very technical details of how **FastAPI** works underneath.

 */
public abstract class Converter<A, B> implements Function<A, B> {
  private final boolean handleNullAutomatically;

  // We lazily cache the reverse view to avoid allocating on every call to reverse().
  @LazyInit @RetainedWith private transient @Nullable Converter<B, A> reverse;

  /** Constructor for use by subclasses. */
  protected Converter() {
    this(true);
  }