Concurrency
===========

This document describes the concurrency considerations for http/2 connections and the connection pool within OkHttp.

## HTTP/2 Connections

The HttpURLConnection API is a blocking API. You make a blocking write to send a request, and a blocking read to receive the response.

#### Blocking APIs

from typing import TypeVar

import anyio.to_thread
from anyio import CapacityLimiter
from starlette.concurrency import iterate_in_threadpool as iterate_in_threadpool  # noqa
from starlette.concurrency import run_in_threadpool as run_in_threadpool  # noqa
from starlette.concurrency import (  # noqa
    run_until_first_complete as run_until_first_complete,
)

_T = TypeVar("_T")


@asynccontextmanager

	go func() {
		defer xioutil.SafeClose(ch)

		concurrency := opts.concurrencyStart

		if opts.autotune {
			// if we have less drives than concurrency then choose
			// only the concurrency to be number of drives to start
			// with - since default '32' might be big and may not
			// complete in total time of 10s.
			if globalEndpoints.NEndpoints() < concurrency {
				concurrency = globalEndpoints.NEndpoints()
			}

 * @since 10.0
 */
@GwtCompatible
public final class Uninterruptibles {
  /** Invokes {@code latch.}{@link CountDownLatch#await() await()} uninterruptibly. */
  @J2ktIncompatible
  @GwtIncompatible // concurrency
  public static void awaitUninterruptibly(CountDownLatch latch) {
    boolean interrupted = false;
    try {
      while (true) {
        try {
          latch.await();
          return;

Committer's Guides
------------------

 * [Concurrency][concurrency]
 * [Debug Logging][debug_logging]
 * [Releasing][releasing]

 [cla]: https://spreadsheets.google.com/spreadsheet/viewform?formkey=dDViT2xzUHAwRkI3X3k5Z0lQM091OGc6MQ&ndplr=1
 [concurrency]: https://square.github.io/okhttp/concurrency/
 [debug_logging]: https://square.github.io/okhttp/debug_logging/

Committer's Guides
------------------

 * [Concurrency][concurrency]
 * [Debug Logging][debug_logging]
 * [Releasing][releasing]

 [cla]: https://spreadsheets.google.com/spreadsheet/viewform?formkey=dDViT2xzUHAwRkI3X3k5Z0lQM091OGc6MQ&ndplr=1
 [concurrency]: https://square.github.io/okhttp/concurrency/
 [debug_logging]: https://square.github.io/okhttp/debug_logging/

### Concurrency and Burgers { #concurrency-and-burgers }

This idea of **asynchronous** code described above is also sometimes called **"concurrency"**. It is different from **"parallelism"**.

**Concurrency** and **parallelism** both relate to "different things happening more or less at the same time".

But the details between *concurrency* and *parallelism* are quite different.

  }

  /**
   * Guides the allowed concurrency among update operations. Used as a hint for internal sizing. The
   * table is internally partitioned to try to permit the indicated number of concurrent updates
   * without contention. Because assignment of entries to these partitions is not necessarily
   * uniform, the actual concurrency observed may vary. Ideally, you should choose a value to

    FakeTicker ticker = new FakeTicker();
    assertThrows(
        IllegalArgumentException.class, () -> ticker.setAutoIncrementStep(-1, NANOSECONDS));
  }

  @GwtIncompatible // concurrency

  public void testConcurrentAdvance() throws Exception {
    FakeTicker ticker = new FakeTicker();

    int numberOfThreads = 64;
    runConcurrentTest(
        numberOfThreads,
        () -> {

  }

  /**
   * Guides the allowed concurrency among update operations. Used as a hint for internal sizing. The
   * table is internally partitioned to try to permit the indicated number of concurrent updates
   * without contention. Because assignment of entries to these partitions is not necessarily
   * uniform, the actual concurrency observed may vary. Ideally, you should choose a value to