CoroutineCallAdapterFactory-启用了Proguard的NoClassDefFoundError

Question

我试图在启用了proguard的情况下使用协程。我收到如下错误：-

W/System.err: java.lang.NoClassDefFoundError: Failed resolution of: Lcom/jakewharton/retrofit2/adapter/kotlin/coroutines/CoroutineCallAdapterFactory;    
W/System.err:     at com.example.test.utils.ApiService$a.a(SourceFile:132)
W/System.err:     at com.example.test.utils.ApiService$a.a(SourceFile:95)    
W/System.err:     at com.example.test.registration.RegistrationActivity.a(SourceFile:166)    
W/System.err:     at com.example.test.registration.RegistrationActivity$a.invokeSuspend(SourceFile:91)    
W/System.err:     at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:32)    
W/System.err:     at kotlinx.coroutines.DispatchedTask$DefaultImpls.run(Dispatched.kt:235)    
W/System.err:     at kotlinx.coroutines.DispatchedContinuation.run(Dispatched.kt:81)    
W/System.err:     at android.os.Handler.handleCallback(Handler.java:815)    
W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:104)    
W/System.err:     at android.os.Looper.loop(Looper.java:207)    
W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:5728)    
W/System.err:     at java.lang.reflect.Method.invoke(Native Method)    
W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:789)    
W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:679)     
W/System.err: Caused by: java.lang.ClassNotFoundException: Didn't find class "com.jakewharton.retrofit2.adapter.kotlin.coroutines.CoroutineCallAdapterFactory" on path: DexPathList[[zip file "/data/app/com.example-1/base.apk"],nativeLibraryDirectories=[/data/app/com.example-1/lib/arm, /vendor/lib, /system/lib]]    
W/System.err:     at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)     
W/System.err:     at java.lang.ClassLoader.loadClass(ClassLoader.java:511)     
W/System.err:     at java.lang.ClassLoader.loadClass(ClassLoader.java:469)     
W/System.err:   ... 14 more    
W/System.err:   Suppressed: java.lang.ClassNotFoundException:com.jakewharton.retrofit2.adapter.kotlin.coroutines.CoroutineCallAdapterFactory    
W/System.err:     at java.lang.Class.classForName(Native Method)    
W/System.err:     at java.lang.BootClassLoader.findClass(ClassLoader.java:781)    
W/System.err:     at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)    
W/System.err:     at java.lang.ClassLoader.loadClass(ClassLoader.java:504)    
W/System.err:       ... 15 more    
W/System.err:   Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available   

我的proguard文件包括：-

##########
# Kotlin
##########
-keep class kotlin.** { *; }
-keep class kotlin.Metadata { *; }
-dontwarn kotlin.**
-keepclassmembers class **$WhenMappings {
    <fields>;
}
-keepclassmembers class kotlin.Metadata {
    public <fields>;
    public <methods>;
}

-keepclassmembers class * {
    static final % *;
    static final java.lang.String *;
}

#-dontwarn org.jetbrains.annotations.**
#Ignore null checks at runtime
-assumenosideeffects class kotlin.jvm.internal.Intrinsics {
    static void checkParameterIsNotNull(java.lang.Object, java.lang.String);
}
-keep class org.jetbrains.kotlin.** { *; }
-keep class org.jetbrains.*
-keep class org.jetbrains.annotations.** { *; }
-keepclassmembers class ** {
  @org.jetbrains.annotations.ReadOnly public *;
}
#############
# Google Play Services
#############
-keep class com.google.android.gms.* {  *; }
-dontwarn com.google.android.gms.**
-keep public class com.google.vending.licensing.ILicensingService
-keep public class com.android.vending.licensing.ILicensingService
-dontnote **ILicensingService
-dontnote com.google.android.gms.gcm.GcmListenerService
-dontnote com.google.android.gms.**


-dontwarn com.google.android.gms.ads.**

#GOOGLE_PLAY_SERVICES
-keep class * extends java.util.ListResourceBundle {
    protected Object[][] getContents();
}

-keep public class com.google.android.gms.common.internal.safeparcel.SafeParcelable {
    public static final *** NULL;
}

-keepnames @com.google.android.gms.common.annotation.KeepName class *
-keepclassmembernames class * {
    @com.google.android.gms.common.annotation.KeepName *;
}

-keepnames class * implements android.os.Parcelable {
    public static final ** CREATOR;
}


#############
# Android Support Lib
#############
-keep class android.support.design.widget.TextInputLayout { *; }

#############
# Retrofit
#############
-dontnote okio.**

#RETROFIT2
-dontwarn retrofit2.**
-keep class retrofit2.** { *; }
-keepattributes Signature
-keepattributes Exceptions

-keepclasseswithmembers class * {
    @retrofit2.http.* <methods>;
}

# OkHttp
-keepattributes Signature
-keepattributes *Annotation*
-keep class okhttp3.** { *; }
-keep interface okhttp3.** { *; }
-dontwarn okhttp3.**

# Okio
-keep class sun.misc.Unsafe { *; }
-dontwarn java.nio.file.*
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement 

我正在对API调用使用retrofit2和jakewharton的协程适配器依赖项。如果禁用了proguard，则工作正常。但是启用proguard时会出现此问题。添加了retrofit2，okHttp，okio和kotlin所需的所有规则。仍然无法解决此问题。