}
	wg.Wait()

	var find User
	err = db.Preload(clause.Associations).Where("id = ?", user.ID).First(&find).Error
	AssertEqual(t, err, nil)
	AssertAssociationCount(t, find, "Languages", int64(count), "after concurrent append")
}

func TestMany2ManyDuplicateBelongsToAssociation(t *testing.T) {
	user1 := User{Name: "TestMany2ManyDuplicateBelongsToAssociation-1", Friends: []*User{

import com.google.common.util.concurrent.ClosingFuture.ClosingCallable;
import com.google.common.util.concurrent.ClosingFuture.DeferredCloser;
import com.google.common.util.concurrent.ClosingFuture.ValueAndCloser;
import com.google.common.util.concurrent.ClosingFuture.ValueAndCloserConsumer;
import java.io.Closeable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.CIFSContext;
import jcifs.Configuration;

import java.net.InetAddress
import java.net.InetSocketAddress
import java.net.Proxy
import java.security.cert.X509Certificate
import java.util.Arrays
import java.util.concurrent.CountDownLatch
import java.util.concurrent.atomic.AtomicInteger
import java.util.concurrent.atomic.AtomicReference
import javax.net.ssl.HostnameVerifier
import javax.net.ssl.SSLPeerUnverifiedException
import javax.net.ssl.SSLSession

import com.google.errorprone.annotations.InlineMe;
import java.time.Duration;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;

/**

import com.google.common.util.concurrent.MoreExecutors;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.Delayed;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ThreadPoolExecutor.CallerRunsPolicy;
import java.util.concurrent.TimeUnit;

/**

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;

### 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。

 */

package com.google.common.util.concurrent;

import static java.lang.Math.min;
import static java.util.concurrent.TimeUnit.NANOSECONDS;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;

import java.io.InputStream;
import java.net.SocketTimeoutException;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicLong;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import jcifs.RuntimeCIFSException;
import jcifs.smb.RequestParam;

/**