Download a file on a worker thread, and get called back when the response is readable. The callback is made after the response headers are ready. Reading the response body may still block. OkHttp doesn't currently offer asynchronous APIs to receive a response body in parts.

=== ":material-language-kotlin: Kotlin"
    ```kotlin
      private val client = OkHttpClient()

      fun run() {

through the use of the <code>Once</code> type.
Multiple threads can execute <code>once.Do(f)</code> for a particular <code>f</code>,
but only one will run <code>f()</code>, and the other calls block
until <code>f()</code> has returned.
</p>

<p class="rule">
The completion of a single call of <code>f()</code> from <code>once.Do(f)</code>
is synchronized before the return of any call of <code>once.Do(f)</code>.

1) Alpha for AWS ALB (Application Load Balancer) integration to Kubernetes Ingress resources.
2) Alpha for CSI specification 0.3 integration to AWS EBS (Elastic Block Store)

pkg syscall (freebsd-386-cgo), type RtMsghdr struct, Version uint8
pkg syscall (freebsd-386-cgo), type Rusage struct, Idrss int32
pkg syscall (freebsd-386-cgo), type Rusage struct, Inblock int32
pkg syscall (freebsd-386-cgo), type Rusage struct, Isrss int32
pkg syscall (freebsd-386-cgo), type Rusage struct, Ixrss int32
pkg syscall (freebsd-386-cgo), type Rusage struct, Majflt int32

pkg encoding/pem, func Decode([]uint8) (*Block, []uint8)
pkg encoding/pem, func Encode(io.Writer, *Block) error
pkg encoding/pem, func EncodeToMemory(*Block) []uint8
pkg encoding/pem, type Block struct
pkg encoding/pem, type Block struct, Bytes []uint8
pkg encoding/pem, type Block struct, Headers map[string]string
pkg encoding/pem, type Block struct, Type string
pkg encoding/xml, const Header ideal-string

* Added block volume support to Cinder volume plugin. ([#64879](https://github.com/kubernetes/kubernetes/pull/64879), [@bertinatto](https://github.com/bertinatto))
* Provided API support for external CSI storage drivers to support block volumes. ([#64723](https://github.com/kubernetes/kubernetes/pull/64723), [@vladimirvivien](https://github.com/vladimirvivien))

   * {@code tailSet} views.
   *
   * {@snippet :
   * NavigableSet<E> set = synchronizedNavigableSet(new TreeSet<E>());
   *  ...
   * synchronized (set) {
   *   // Must be in the synchronized block
   *   Iterator<E> it = set.iterator();
   *   while (it.hasNext()) {
   *     foo(it.next());
   *   }
   * }
   * }
   *
   * <p>or:
   *
   * {@snippet :

              errorMessage.set("Cancel call exited before future was complete.");
            }
          });
      try {
        future.get();
      } catch (Throwable t) {
        // Ignore, we just wanted to block.
      }
      String error = errorMessage.get();
      assertWithMessage(error).that(error).isNull();
    }
    executor.shutdown();
  }

  /**

            }
            // Ensure atomic cleanup of all resources
            synchronized (this) {
                // Double-check usage count within synchronized block
                if (this.usageCount.get() != 0) {
                    return; // Another thread acquired the session
                }

                if (this.transportAcquired.compareAndSet(true, false)) {

  @IgnoreJRERequirement // No more dangerous than wherever the caller got the Duration from
  private static long toNanosSaturated(Duration duration) {
    // Using a try/catch seems lazy, but the catch block will rarely get invoked (except for
    // durations longer than approximately +/- 292 years).
    try {
      return duration.toNanos();
    } catch (ArithmeticException tooBig) {