CurrentSendCalls int64 // CurrentSendCalls is the number of concurrent async Send calls to all targets
	CurrentQueue     int   // Populated if target has a store.
	TotalEvents      int64
	FailedEvents     int64 // Number of failed events per target
}

// TargetList - holds list of targets indexed by target ID.
type TargetList struct {
	// The number of concurrent async Send calls to all targets
	currentSendCalls  atomic.Int64

import java.nio.charset.UnsupportedCharsetException;
import java.util.ConcurrentModificationException;
import java.util.NoSuchElementException;
import java.util.concurrent.CancellationException;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeoutException;
import junit.framework.AssertionFailedError;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

 * limitations under the License.
 */
package okhttp3

import assertk.assertThat
import assertk.assertions.isEqualTo
import assertk.assertions.isTrue
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors
import mockwebserver3.MockResponse
import mockwebserver3.MockWebServer
import mockwebserver3.junit5.StartStop
import okhttp3.testing.PlatformRule
import org.junit.jupiter.api.BeforeEach

import java.security.GeneralSecurityException;
import java.security.Security;
import java.util.Arrays;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

 */
package okhttp3

import java.io.Closeable
import java.util.concurrent.CopyOnWriteArraySet
import java.util.logging.ConsoleHandler
import java.util.logging.Handler
import java.util.logging.Level
import java.util.logging.LogRecord
import java.util.logging.Logger
import java.util.logging.SimpleFormatter
import kotlin.reflect.KClass
import okhttp3.internal.concurrent.TaskRunner
import okhttp3.internal.http2.Http2

### 並行漢堡

你和你的戀人去速食店，排隊等候時，收銀員正在幫排在你前面的人點餐。😍

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

輪到你了，你給你與你的戀人點了兩個豪華漢堡。🍔🍔

<img src="/img/async/concurrent-burgers/concurrent-burgers-02.png" class="illustration">

收銀員通知廚房準備你的漢堡（儘管他們還在為前面其他顧客準備食物）。

<img src="/img/async/concurrent-burgers/concurrent-burgers-03.png" class="illustration">

之後你完成付款。💸

收銀員給你一個號碼牌。

  // http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/main/java/util/concurrent/

  /** The queued items */
  final E[] items;

  /** items index for next take, poll or remove */
  int takeIndex;

  /** items index for next put, offer, or add. */
  int putIndex;

  /** Number of items in the queue */
  private int count;

  /*
   * Concurrency control uses the classic two-condition algorithm
   * found in any textbook.

import android.annotation.SuppressLint
import java.util.concurrent.ThreadFactory
import java.util.concurrent.TimeUnit
import java.util.logging.Handler
import java.util.logging.Level
import java.util.logging.LogManager
import java.util.logging.LogRecord
import java.util.logging.Logger
import okhttp3.internal.buildConnectionPool
import okhttp3.internal.concurrent.TaskRunner
import okhttp3.internal.concurrent.withLock

        if (offset + SIGNATURE_OFFSET + SIGNATURE_LENGTH > data.length) {
            throw new IllegalArgumentException("Signature field exceeds data buffer size");
        }

        // Use fine-grained locking for better concurrency
        this.signingLock.lock();
        try {
            if (this.closed) {
                throw new IllegalStateException("SigningDigest is closed");
            }

            // zero out signature field

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3

import java.util.concurrent.LinkedBlockingQueue
import java.util.concurrent.TimeUnit
import java.util.logging.Handler
import java.util.logging.Level
import java.util.logging.LogRecord
import java.util.logging.Logger
import org.junit.jupiter.api.extension.AfterEachCallback