"expireAfterWrite was already set to %s ns",
        expireAfterWriteNanos);
    checkArgument(duration >= 0, "duration cannot be negative: %s %s", duration, unit);
    this.expireAfterWriteNanos = unit.toNanos(duration);
    return this;
  }

  @SuppressWarnings("GoodTime") // nanos internally, should be Duration
  long getExpireAfterWriteNanos() {

    connection.writePingAndAwaitPong()
    val elapsedNanos = System.nanoTime() - pingAtNanos
    assertThat(elapsedNanos).isGreaterThan(0L)
    assertThat(elapsedNanos).isLessThan(TimeUnit.SECONDS.toNanos(1))

    // Verify the peer received what was expected.
    val pingFrame = peer.takeFrame()
    assertThat(pingFrame.type).isEqualTo(Http2.TYPE_PING)
    assertThat(pingFrame.streamId).isEqualTo(0)