But by following the steps above, it will be able to do some performance optimizations.

## Technical Details

Modern versions of Python have support for **"asynchronous code"** using something called **"coroutines"**, with **`async` and `await`** syntax.

Let's see that phrase by parts in the sections below:

* **Asynchronous Code**
* **`async` and `await`**
* **Coroutines**

## Asynchronous Code

    val rule = MockWebServerRule()
    val called = AtomicBoolean()
    val statement: Statement =
      rule.apply(
        object : Statement() {
          override fun evaluate() {
            called.set(true)
            rule.server.url("/").toUrl().openConnection().connect()
          }
        },
        Description.EMPTY,
      )
    statement.evaluate()
    assertThat(called.get()).isTrue()
    try {

1. Creating a PR and observing the presubmit test results
2. Running the CI scripts locally, as explained below
3. **Google employees only**: Google employees can use an internal-only tool
called "MLCI" that makes testing more convenient: it can execute any full CI job
against a pending change. Search for "MLCI" internally to find it.

You may invoke a CI script of your choice by following these instructions:

```bash

object HttpMethod {
  @JvmStatic // Despite being 'internal', this method is called by popular 3rd party SDKs.
  fun invalidatesCache(method: String): Boolean =
    (
      method == "POST" || method == "PATCH" || method == "PUT" ||
        method == "DELETE" || method == "MOVE"
    )

  @JvmStatic // Despite being 'internal', this method is called by popular 3rd party SDKs.
  fun requiresRequestBody(method: String): Boolean =
    (

## pytest.mark.anyio

If we want to call asynchronous functions in our tests, our test functions have to be asynchronous. AnyIO provides a neat plugin for this, that allows us to specify that some test functions are to be called asynchronously.

## HTTPX

Even if your **FastAPI** application uses normal `def` functions instead of `async def`, it is still an `async` application underneath.

import okio.IOException

interface Callback {
  /**
   * Called when the request could not be executed due to cancellation, a connectivity problem or
   * timeout. Because networks can fail during an exchange, it is possible that the remote server
   * accepted the request before the failure.
   */
  fun onFailure(
    call: Call,
    e: IOException,
  )

  /**

  /**
   * Immediately closes the socket connection if it's currently held. Use this to interrupt an
   * in-flight request from any thread. It's the caller's responsibility to close the request body
   * and response body streams; otherwise resources may be leaked.
   *
   * This method is safe to be called concurrently, but provides limited guarantees. If a transport

import okhttp3.ExperimentalOkHttpApi
import okio.BufferedSink

/**
 * The body of a [MockResponse].
 *
 * Unlike [okhttp3.ResponseBody], this interface is designed to be implemented by writers and not
 * called by readers.
 */
@ExperimentalOkHttpApi
interface MockResponseBody {
  /** The length of this response in bytes, or -1 if unknown. */
  val contentLength: Long

  @Throws(IOException::class)

    }
  }

  private fun logEvent(e: ConnectionEvent) {
    if (e.connection != null) {
      assertThat(Thread.holdsLock(e.connection), "Called with lock $${e.connection}")
        .isFalse()
    }
    for (lock in forbiddenLocks) {
      assertThat(Thread.holdsLock(lock), "Called with lock $lock")
        .isFalse()
    }

    if (enforceOrder) {
      checkForStartEvent(e)
    }

        val generatedTopLevelClassifiers = declarationGenerators
            .asSequence()
            .flatMap {
                // FIXME this function should be called only once during plugin's lifetime, so this usage is not really correct (2)
                it.getTopLevelClassIds()
            }
            .filter { it.packageFqName == packageFqName }
            .map { it.shortClassName }