HTTP/1.1. We also reimplemented our websocket client to use this new mechanism.

 *  New: The `okhttp-zstd` module negotiates [Zstandard (zstd)][zstd] compression with servers that
    support it. It integrates a new (unstable) [ZSTD-KMP] library, also from Square. Enable it like
    this:

    ```kotlin
    val client = OkHttpClient.Builder()
      .addInterceptor(CompressionInterceptor(Zstd, Gzip))
      .build()
    ```

It won't do any data conversion with Pydantic models, it won't convert the contents to any type, etc.

This gives you a lot of **flexibility**. You can return any data type, override any data declaration or validation, etc.

It also gives you a lot of **responsibility**. You have to make sure that the data you return is correct, in the correct format, that it can be serialized, etc.

A common choice is Jinja2, the same one used by Flask and other tools.

There are utilities to configure it easily that you can use directly in your **FastAPI** application (provided by Starlette).

## Install dependencies { #install-dependencies }

Make sure you create a [virtual environment](../virtual-environments.md), activate it, and install `jinja2`:

<div class="termy">

```console
$ pip install jinja2

---> 100%
```

/*
 * © 2016 AgNO3 Gmbh & Co. KG
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of

* What test cases should it have? What could go wrong?
* How will it roughly be implemented? We'll happily provide code pointers to save you time.

We may ask you to answer these questions directly in the GitHub issue or (for large changes) in a shared Google Doc.

    private boolean foundAndRemovedExactReference(Iterable<E> elements, E target) {
      for (Iterator<E> it = elements.iterator(); it.hasNext(); ) {
        E element = it.next();
        if (element == target) {
          it.remove();
          return true;
        }
      }
      return false;
    }

    for details.

    The summary is that it ignores one file in favor of the other.
    util.concurrent, like nearly all our packages, has two .gwt.xml files: one
    for prod and one for tests. However, unlike our other packages, as of this
    writing it has test supersource but no prod supersource.

    GWT happens to use the prod .gwt.xml, so it looks for no supersource for
    tests, either. This causes it to fail to find AtomicLongMapTest.

// and checks whether they are well-formed. It returns the sealed object key
// on success. If the metadata contains both, a KMS master key ID and a sealed
// KMS data key it returns both. If the metadata does not contain neither a
// KMS master key ID nor a sealed KMS data key it returns an empty keyID and
// KMS data key. Otherwise, it returns an error.

## Older `GraphQLApp` from Starlette { #older-graphqlapp-from-starlette }

Previous versions of Starlette included a `GraphQLApp` class to integrate with [Graphene](https://graphene-python.org/).

It was deprecated from Starlette, but if you have code that used it, you can easily **migrate** to [starlette-graphene3](https://github.com/ciscorn/starlette-graphene3), that covers the same use case and has an **almost identical interface**.

/// tip

    propagateIfInstanceOf(throwable, declaredType1);
    propagateIfPossible(throwable, declaredType2);
  }

  /**
   * Propagates {@code throwable} as-is if it is an instance of {@link RuntimeException} or {@link
   * Error}, or else as a last resort, wraps it in a {@code RuntimeException} and then propagates.
   *
   * <p>This method always throws an exception. The {@code RuntimeException} return type allows