ITDmlReturningTest.dmlReturningWithExecuteQueryAsync[Dialect = POSTGRESQL] is flaky

[ERROR] Tests run: 14, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 12.31 s <<< FAILURE! -- in com.google.cloud.spanner.it.ITDmlReturningTest
[ERROR] com.google.cloud.spanner.it.ITDmlReturningTest.dmlReturningWithExecuteQueryAsync[Dialect = POSTGRESQL] -- Time elapsed: 1.281 s <<< FAILURE!
org.junit.ComparisonFailure: expected:<13-boo[2]> but was:<13-boo[1]>
    at org.junit.Assert.assertEquals(Assert.java:117)
    at org.junit.Assert.assertEquals(Assert.java:146)
    at com.google.cloud.spanner.it.ITDmlReturningTest.dmlReturningWithExecuteQueryAsync(ITDmlReturningTest.java:332)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.junit.rules.ExternalResource$1.evaluate(ExternalResource.java:54)
    at org.junit.rules.RunRules.evaluate(RunRules.java:20)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.junit.runners.Suite.runChild(Suite.java:128)
    at org.junit.runners.Suite.runChild(Suite.java:27)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.apache.maven.surefire.junitcore.JUnitCore.run(JUnitCore.java:49)
    at org.apache.maven.surefire.junitcore.JUnitCoreWrapper.createRequestAndRun(JUnitCoreWrapper.java:120)
    at org.apache.maven.surefire.junitcore.JUnitCoreWrapper.executeLazy(JUnitCoreWrapper.java:105)
    at org.apache.maven.surefire.junitcore.JUnitCoreWrapper.execute(JUnitCoreWrapper.java:77)
    at org.apache.maven.surefire.junitcore.JUnitCoreWrapper.execute(JUnitCoreWrapper.java:69)
    at org.apache.maven.surefire.junitcore.JUnitCoreProvider.invoke(JUnitCoreProvider.java:146)
    at org.apache.maven.surefire.booter.ForkedBooter.runSuitesInProcess(ForkedBooter.java:385)
    at org.apache.maven.surefire.booter.ForkedBooter.execute(ForkedBooter.java:162)
    at org.apache.maven.surefire.booter.ForkedBooter.run(ForkedBooter.java:507)
    at org.apache.maven.surefire.booter.ForkedBooter.main(ForkedBooter.java:495)
googleapis / java-spanner

ITDmlReturningTest.dmlReturningWithExecuteQueryAsync[Dialect = POSTGRESQL] is flaky #3274
