#### Http2Writer

Socket writes are guarded by the Http2Writer. Only one stream can write at a time so that messages are not interleaved. Writes are either made by application-layer threads or the do-stuff-later pool.

### Holding multiple locks

{* ../../docs_src/advanced_middleware/tutorial002.py hl[2,6:8] *}

The following arguments are supported:

* `allowed_hosts` - A list of domain names that should be allowed as hostnames. Wildcard domains such as `*.example.com` are supported for matching subdomains. To allow any hostname either use `allowed_hosts=["*"]` or omit the middleware.

Here are the general instructions for the tasks you can perform.

Thanks a lot for your help. 🙇

## Be Nice

First of all, be nice. 😊

You probably are super nice if you were added to the team, but it's worth mentioning it. 🤓

### When Things are Difficult

  /**
   * Adds {@code equalityGroup} with objects that are supposed to be equal to each other and not
   * equal to any other equality groups added to this tester.
   *
   * <p>The {@code @Nullable} annotations on the {@code equalityGroup} parameter imply that the
   * objects, and the array itself, can be null. That is for programmer convenience, when the
   * objects come from factory methods that are themselves {@code @Nullable}. In reality neither the

Despite this expectation in SotW, due to a quirk in the protocol we can actually enable one of our most important optimizations. XDS...

Copyright (c) 2012 The Go Authors. All rights reserved.
Copyright (c) 2019 Klaus Post. All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

   * Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
   * Redistributions in binary form must reproduce the above

   developers and others in the free software community to coordinate our efforts.

 * **Be pragmatic**: Questions are encouraged and should be asked early in the process to avoid
   problems later. Be thoughtful and considerate when seeking out the appropriate forum for your
   questions. Those who are asked should be responsive and helpful.

 * **Step down considerately**: Members of every project come and go. When somebody leaves or

  private Objects() {}

  /**
   * Determines whether two possibly-null objects are equal. Returns:
   *
   * <ul>
   *   <li>{@code true} if {@code a} and {@code b} are both null.
   *   <li>{@code true} if {@code a} and {@code b} are both non-null and they are equal according to
   *       {@link Object#equals(Object)}.
   *   <li>{@code false} in all other situations.
   * </ul>
   *

/**
 * Constrains which certificates are trusted. Pinning certificates defends against attacks on
 * certificate authorities. It also prevents connections through man-in-the-middle certificate
 * authorities either known or unknown to the application's user.
 * This class currently pins a certificate's Subject Public Key Info as described on
 * [Adam Langley's Weblog][langley]. Pins are either base64 SHA-256 hashes as in

You should probably **not** use this base Docker image (or any other similar one).

If you are using **Kubernetes** (or others) and you are already setting **replication** at the cluster level, with multiple **containers**. In those cases, you are better off **building an image from scratch** as described above: [Build a Docker Image for FastAPI](#build-a-docker-image-for-fastapi).