#### Per-Connection Locks

Each connection has its own lock. The connections in the pool are all in a `ConcurrentLinkedQueue`. Due to data races, iterators of this queue may return removed connections. Callers must check the connection's `noNewExchanges` property before using connections from the pool.

The connection lock is never held while doing I/O (even closing a socket) to prevent contention.

  abstract void setCountCheckReturnValue(E element, int count);

  /**
   * Call the {@code setCount()} method under test, but do not check its return value. Callers
   * should use this method over {@link #setCountCheckReturnValue(Object, int)} when they expect
   * {@code setCount()} to throw an exception, as checking the return value could produce an

  - Deployment:
    - deployment/index.md
    - deployment/versions.md
    - deployment/https.md
    - deployment/manually.md
    - deployment/concepts.md
    - deployment/cloud.md
    - deployment/server-workers.md
    - deployment/docker.md
  - How To - Recipes:
    - how-to/index.md
    - how-to/general.md
    - how-to/graphql.md
    - how-to/custom-request-and-route.md
    - how-to/conditional-openapi.md

      return getDoneValue(requireNonNull(valueField));
    }
    // If we get here then we have remainingNanos < SPIN_THRESHOLD_NANOS and there is no node on the
    // waiters list
    while (remainingNanos > 0) {
      localValue = valueField;
      if (localValue != null & notInstanceOfDelegatingToFuture(localValue)) {
        return getDoneValue(localValue);
      }

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    }

    /**
     * Sets the level and returns this.
     *
     * This was deprecated in OkHttp 4.0 in favor of the [level] val. In OkHttp 4.3 it is
     * un-deprecated because Java callers can't chain when assigning Kotlin vals. (The getter remains
     * deprecated).
     */
    fun setLevel(level: Level) =
      apply {
        this.level = level
      }

    @JvmName("-deprecated_level")

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