We've started seeing this trace on our android builds coming from R8. We use version 2.0.18, and have a few cases where R8's serviceloading improvements could be kicking in (coroutines, auto-value-gson, maybe others).

```
[2020-02-04T00:05:36.092Z] Caused by: java.lang.IllegalArgumentException: Multiple entries with same key: Method $$ServiceLoaderMethods.$load0 Proto L java.util.Iterator =Encoded method Method $$ServiceLoaderMethods.$load0 Proto L java.util.Iterator and Method $$ServiceLoaderMethods.$load0 Proto L java.util.Iterator =Encoded method Method $$ServiceLoaderMethods.$load0 Proto L java.util.Iterator
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.com.google.common.collect.ImmutableMap.checkNoConflict(ImmutableMap.java:190)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.com.google.common.collect.RegularImmutableMap.checkNoConflictInKeyBucket(RegularImmutableMap.java:109)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.com.google.common.collect.RegularImmutableMap.fromEntryArray(RegularImmutableMap.java:95)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.com.google.common.collect.ImmutableMap$Builder.build(ImmutableMap.java:373)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.graph.AppInfo.computeDefinitions(AppInfo.java:111)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.graph.AppInfo.getDefinitions(AppInfo.java:195)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.graph.AppInfo.definitionFor(AppInfo.java:175)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.graph.AppView.definitionFor(AppView.java:186)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.analysis.ClassInitializationAnalysis$InstructionUtils.forInvokeStatic(ClassInitializationAnalysis.java:356)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.code.InvokeStatic.definitelyTriggersClassInitialization(InvokeStatic.java:155)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.optimize.info.MethodOptimizationInfoCollector.lambda$triggersClassInitializationBeforeSideEffect$1(MethodOptimizationInfoCollector.java:627)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.optimize.info.MethodOptimizationInfoCollector.alwaysTriggerExpectedEffectBeforeAnythingElse(MethodOptimizationInfoCollector.java:668)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.optimize.info.MethodOptimizationInfoCollector.triggersClassInitializationBeforeSideEffect(MethodOptimizationInfoCollector.java:623)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.optimize.info.MethodOptimizationInfoCollector.identifyInvokeSemanticsForInlining(MethodOptimizationInfoCollector.java:606)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.optimize.info.MethodOptimizationInfoCollector.collectMethodOptimizationInfo(MethodOptimizationInfoCollector.java:123)
[2020-02-04T00:05:36.092Z] at com.android.tools.r8.ir.conversion.IRConverter.collectOptimizationInfo(IRConverter.java:1468)
[2020-02-04T00:05:36.093Z] at com.android.tools.r8.ir.conversion.IRConverter.optimize(IRConverter.java:1421)
[2020-02-04T00:05:36.093Z] at com.android.tools.r8.ir.conversion.IRConverter.rewriteCodeInternal(IRConverter.java:1096)
[2020-02-04T00:05:36.093Z] at com.android.tools.r8.ir.conversion.IRConverter.rewriteCode(IRConverter.java:1060)
[2020-02-04T00:05:36.093Z] at com.android.tools.r8.ir.conversion.IRConverter.processMethod(IRConverter.java:1041)
[2020-02-04T00:05:36.093Z] at com.android.tools.r8.ir.conversion.IRConverter.lambda$optimize$4(IRConverter.java:665)
[2020-02-04T00:05:36.093Z] at com.android.tools.r8.utils.ThreadUtils.lambda$processItems$0(ThreadUtils.java:25)
```