Failed: Default socket.io support / should allow disconnecting from a namespace

https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true

[info] [error] 2022-05-13 17:18:52,371 application - 
[187](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:187)
[info] ! @7nj615jmg - Internal server error, for (GET) [/socket.io/?EIO=3&transport=polling&t=O2-RYd3&sid=7b34b0b4-4d11-47da-a980-ee053c5e730a] ->
[188](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:188)
[info]  
[189](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:189)
[info] play.api.http.HttpErrorHandlerExceptions$$anon$1: Execution exception[[UnknownSessionId: Unknown session id: 7b34b0b4-4d11-47da-a980-ee053c5e730a]]
[190](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:190)
[info] 	at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:351)
[191](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:191)
[info] 	at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:267)
[192](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:192)
[info] 	at play.core.server.AkkaHttpServer$$anonfun$1.applyOrElse(AkkaHttpServer.scala:448)
[193](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:193)
[info] 	at play.core.server.AkkaHttpServer$$anonfun$1.applyOrElse(AkkaHttpServer.scala:446)
[194](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:194)
[info] 	at scala.concurrent.Future.$anonfun$recoverWith$1(Future.scala:417)
[195](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:195)
[info] 	at scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:41)
[196](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:196)
[info] 	at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
[197](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:197)
[info] 	at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
[198](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:198)
[info] 	at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:92)
[199](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:199)
[info] 	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[200](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:200)
[info] Caused by: play.engineio.UnknownSessionId: Unknown session id: 7b34b0b4-4d11-47da-a980-ee053c5e730a
[201](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:201)
[info] [error] 2022-05-13 17:18:52,421 application - 
[202](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:202)
[info] ! @7nj615joi - Internal server error, for (GET) [/socket.io/?EIO=3&transport=polling&t=O2-RYd-&sid=3dc51757-81d2-4f8c-87ee-057d6e252b9c] ->
[203](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:203)
[info]  
[204](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:204)
[info] play.api.http.HttpErrorHandlerExceptions$$anon$1: Execution exception[[UnknownSessionId: Unknown session id: 3dc51757-81d2-4f8c-87ee-057d6e252b9c]]
[205](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:205)
[info] 	at play.api.http.HttpErrorHandlerExceptions$.throwableToUsefulException(HttpErrorHandler.scala:351)
[206](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:206)
[info] 	at play.api.http.DefaultHttpErrorHandler.onServerError(HttpErrorHandler.scala:267)
[207](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:207)
[info] 	at play.core.server.AkkaHttpServer$$anonfun$1.applyOrElse(AkkaHttpServer.scala:448)
[208](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:208)
[info] 	at play.core.server.AkkaHttpServer$$anonfun$1.applyOrElse(AkkaHttpServer.scala:446)
[209](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:209)
[info] 	at scala.concurrent.Future.$anonfun$recoverWith$1(Future.scala:417)
[210](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:210)
[info] 	at scala.concurrent.impl.Promise.$anonfun$transformWith$1(Promise.scala:41)
[211](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:211)
[info] 	at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64)
[212](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:212)
[info] 	at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:55)
[213](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:213)
[info] 	at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:92)
[214](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:214)
[info] 	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[215](https://github.com/playframework/play-socket.io/runs/6427075607?check_suite_focus=true#step:9:215)
[info] Caused by: play.engineio.UnknownSessionId: Unknown session id: 3dc51757-81d2-4f8c-87ee-057d6e252b9c

Start with the linked CI run and the /socket.io polling requests that fail with play.engineio.UnknownSessionId. Trace the namespace-disconnect flow through the Play socket.io integration and identify the relevant test entry point. Done means disconnecting from a namespace no longer produces unknown-session errors.