stream.takeHeaders()
    }
    val elapsedNanos = System.nanoTime() - startNanos
    awaitWatchdogIdle()
    // 200ms delta
    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedNanos).toDouble())
      .isCloseTo(500.0, 200.0)
    assertThat(connection.openStreamCount()).isEqualTo(0)

    // Verify the peer received what was expected.
    assertThat(peer.takeFrame().type).isEqualTo(Http2.TYPE_HEADERS)

                if (value instanceof final Number num) {
                    value = num.doubleValue();
                } else {
                    value = DfTypeUtil.toDouble(value.toString());
                }
            }
            return new Pair<>(key, value);
        }).collect(Collectors.toMap(Pair::getFirst, Pair::getSecond));
    }

        "stream was reset: PROTOCOL_ERROR",
      )
    }
    val elapsedUntilFailure = System.nanoTime() - executeAtNanos
    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedUntilFailure).toDouble())
      .isCloseTo(1000.0, 250.0)

    // Confirm a single ping was sent but not acknowledged.
    val logs = testLogHandler.takeAll()
    assertThat(countFrames(logs, "FINE: >> 0x00000000     8 PING          "))

 */
// TODO(kak): Consider removing @CanIgnoreReturnValue from this class.
@J2ktIncompatible
@GwtIncompatible
@SuppressWarnings({
  "GuardedBy", // TODO(b/35466881): Fix or suppress.
  "nullness", // too much trouble for the payoff
})
@NullUnmarked // TODO(cpovirk): Annotate for nullness.
final class MapMakerInternalMap<
        K,
        V,
        E extends MapMakerInternalMap.InternalEntry<K, V, E>,