AssertionError occured while running RecyclerViewSample

hi,
i tried to run the RecyclerViewSample, but an error occured with the following information:
```
java.lang.AssertionError: Activity never becomes requested state "[RESUMED, DESTROYED, STARTED, CREATED]" (last lifecycle transition = "PRE_ON_CREATE")
at androidx.test.core.app.ActivityScenario.waitForActivityToBecomeAnyOf(ActivityScenario.java:279)
at androidx.test.core.app.ActivityScenario.launch(ActivityScenario.java:211)
at androidx.test.core.app.ActivityScenario.launch(ActivityScenario.java:184)
at androidx.test.ext.junit.rules.ActivityScenarioRule.lambda$new$0$ActivityScenarioRule(ActivityScenarioRule.java:68)
at androidx.test.ext.junit.rules.ActivityScenarioRule$$Lambda$0.get(Unknown Source:2)
at androidx.test.ext.junit.rules.ActivityScenarioRule.before(ActivityScenarioRule.java:82)
at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:46)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at androidx.test.ext.junit.runners.AndroidJUnit4.run(AndroidJUnit4.java:104)
at org.junit.runners.Suite.runChild(Suite.java:128)
at org.junit.runners.Suite.runChild(Suite.java:27)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at org.junit.runner.JUnitCore.run(JUnitCore.java:115)
at androidx.test.internal.runner.TestExecutor.execute(TestExecutor.java:56)
at androidx.test.runner.AndroidJUnitRunner.onStart(AndroidJUnitRunner.java:388)
at android.app.Instrumentation$InstrumentationThread.run(Instrumentation.java:2252)

```
i don't why, anybody can help me ?

Beginne damit, den Fehler in RecyclerViewSample zu reproduzieren und den Stacktrace des ActivityScenario-Starts zu lesen, der während des PRE_ON_CREATE-Lebenszyklusübergangs endet. Das Problem ist behoben, wenn das Beispiel ohne den gemeldeten AssertionError gestartet wird.

Vom Indexierungsmodell aus dem Issue-Text verfasst.