将Spark框架从1.6切换到2.1后，运行我的测试会导致出现以下错误：
[info] java.lang.AssertionError: assertion failed: copyAndReset must return a zero value copy
[info] at scala.Predef$.assert(Predef.scala:170)
[info] at org.apache.spark.util.AccumulatorV2.writeReplace(AccumulatorV2.scala:163)
[info] at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
[info] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[info] at java.lang.reflect.Method.invoke(Method.java:497)
[info] at java.io.ObjectStreamClass.invokeWriteReplace(ObjectStreamClass.java:1075)
[info] at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1136)
[info] at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1548)
[info] at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1509)
[info] at java.io.ObjectOutputStream.writeOrdinaryObject(ObjectOutputStream.java:1432)
[info] ...
任何想法发生了什么以及如何解决这个问题？