You stand in line while several (let's say 8) cashiers that at the same time are cooks take the orders from the people in front of you.

Everyone before you is waiting for their burgers to be ready before leaving the counter because each of the 8 cashiers goes and prepares the burger right away before getting the next order.

<img src="/img/async/parallel-burgers/parallel-burgers-01.png" class="illustration">

    * So, the **certificate and encryption** handling is done **before HTTP**.
* **TCP doesn't know about "domains"**. Only about IP addresses.
    * The information about the **specific domain** requested goes in the **HTTP data**.
* The **HTTPS certificates** "certify" a **certain domain**, but the protocol and encryption happen at the TCP level, **before knowing** which domain is being dealt with.

   *
   * This is typically invoked immediately before bytes are returned to the application. If the
   * response body is empty this is invoked immediately before returning that to the application.
   *
   * If the application closes the response body before attempting a read, this is invoked at the
   * time it is closed.
   *

## Previous Steps Before Starting

There are many cases where you want to perform some steps **before starting** your application.

For example, you might want to run **database migrations**.

But in most cases, you will want to perform these steps only **once**.

So, you will want to have a **single process** to perform those **previous steps**, before starting the application.

    operators before adopting it.

 *  New in okhttp-android: `HttpLoggingInterceptor.androidLogging()` and
    `LoggingEventListener.androidLogging()` write HTTP calls or events to Logcat.

 *  New: `OkHttpClient.webSocketCloseTimeout` configures how long a web socket connection will wait
    for a graceful shutdown before it performs an abrupt shutdown.

This guide will help you to...

* maximize the chance of your changes being accepted
* work on the Gradle code base
* get help if you encounter trouble

## Before you start

Before starting to work on a feature or a bug fix, please open an issue to discuss the use case or bug with us. This can save everyone a lot of time and frustration.

# Contributing guidelines

## Pull Request Checklist

Before sending your pull requests, make sure you do the following:

-   Read the [contributing guidelines](CONTRIBUTING.md).
-   Read the [Code of Conduct](CODE_OF_CONDUCT.md).
-   Ensure you have signed the
    [Contributor License Agreement (CLA)](https://cla.developers.google.com/).
-   Check if your changes are consistent with the

          println("TLSv1.2 traffic will be logged automatically and available via wireshark")
        }

        if (tlsVersions.contains(TLS_1_3)) {
          println("TLSv1.3 requires an external command run before first traffic is sent")
          println("Follow instructions at https://github.com/neykov/extract-tls-secrets for TLSv1.3")
          println("Pid: ${ProcessHandle.current().pid()}")

          Thread.sleep(10000)
        }

    Make sure you [Upgrade the FastAPI version](../deployment/versions.md#upgrading-the-fastapi-versions){.internal-link target=_blank} to at least 0.95.1 before using `Annotated`.

## Use `Annotated` in the type for the `q` parameter

Remember I told you before that `Annotated` can be used to add metadata to your parameters in the [Python Types Intro](../python-types.md#type-hints-with-metadata-annotations){.internal-link target=_blank}?

        }
        .build()

    executeSynchronously(request)
      .assertBody("body")

    assertThat(client.routeDatabase.failedRoutes).isEmpty()
    // TODO check if we expect a second request to server1, before attempting server2
    assertThat(server1.requestCount).isEqualTo(2)
    assertThat(server2.requestCount).isEqualTo(1)

    assertThat(clientTestRule.recordedConnectionEventTypes()).containsExactly(
      "ConnectStart",