* Traefik (that can also handle certificate renewals)
* Caddy (that can also handle certificate renewals)
* Nginx
* HAProxy

## Let's Encrypt { #lets-encrypt }

Before Let's Encrypt, these **HTTPS certificates** were sold by trusted third parties.

The process to acquire one of these certificates used to be cumbersome, require quite some paperwork and the certificates were quite expensive.

     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can
     * return the same element. This enables the assertion to pass and the reference iterator to

            .removalListener(listener)
            .ticker(ticker)
            .build();
    cache.put(1, 1);
    ticker.advance(10, MINUTES);
    cache.invalidateAll();

    assertThat(listener.poll().getCause()).isEqualTo(RemovalCause.EXPIRED);
  }

  private void runRemovalScheduler(
      LoadingCache<String, Integer> cache,
      CountingRemovalListener<String, Integer> removalListener,

      "take plan 1",
      "plan 0 cancel",
      "plan 0 TCP connect canceled",
    )
  }

  private fun assertEvents(vararg expected: String) {
    val actual = generateSequence { routePlanner.events.poll() }.toList()
    assertThat(actual).containsExactly(*expected)
  }

  private val Int.ms: Long
    get() = this * 1_000_000L

      while (true) {
        Future<T> f = futureQueue.poll();
        if (f == null) {
          if (ntasks > 0) {
            --ntasks;
            futures.add(submitAndAddQueueListener(executorService, it.next(), futureQueue));
            ++active;
          } else if (active == 0) {
            break;
          } else if (timed) {
            f = futureQueue.poll(timeoutNanos, NANOSECONDS);
            if (f == null) {

        }
        this.toRemove.add((SmbTransportImpl) trans);
    }

    private void cleanup() {
        SmbTransportImpl trans;
        while ((trans = this.toRemove.poll()) != null) {
            if (log.isDebugEnabled()) {
                log.debug("Removing transport connection " + trans + " (" + System.identityHashCode(trans) + ")");
            }
            this.connections.remove(trans);

						continue
					}

					if err = Rename(pathJoin(currentDataPath, entry), pathJoin(legacyDataPath, entry)); err != nil {
						// Any failed rename calls un-roll previous transaction.
						s.deleteFile(dstVolumeDir, legacyDataPath, true, false)

						return res, osErrToFileErr(err)
					}
				}
			}
		}
	}

     * The previous version, <code>apiVersion: extensions/v1beta1</code>, is still supported.  Even if you roll back to 1.1, the objects created using
the new apiVersion will still be accessible, using the old version.   You can
continue to use your existing JSON and YAML files until you are ready to switch

     * @param streamDependency the stream ID this stream is dependent on.
     * @param weight relative proportion of priority in `[1..256]`.
     * @param exclusive inserts this stream ID as the sole child of `streamDependency`.
     */
    fun priority(
      streamId: Int,
      streamDependency: Int,
      weight: Int,
      exclusive: Boolean,
    )

    /**

     * not in {@link #nextElements}, this method throws an {@link UnknownElementException}.
     *
     * <p>This method is used when testing iterators without a known ordering. We poll the target
     * iterator's next element and pass it to the reference iterator through this method so it can
     * return the same element. This enables the assertion to pass and the reference iterator to