Use an AtomicBoolean instead of a MutableStateFlow to atomically init the RustMatrixRoom. Should improve #951.

libraries/matrix/impl/src/main/kotlin/io/element/android/libraries/matrix/impl/room/RustMatrixRoom.kt

@@ -65,6 +65,7 @@ import org.matrix.rustcomponents.sdk.genTransactionId
 import org.matrix.rustcomponents.sdk.messageEventContentFromMarkdown
 import timber.log.Timber
 import java.io.File
+import java.util.concurrent.atomic.AtomicBoolean
 
 @OptIn(ExperimentalCoroutinesApi::class)
 class RustMatrixRoom(
@@ -88,7 +89,7 @@ class RustMatrixRoom(
 
     private val roomCoroutineScope = sessionCoroutineScope.childScope(coroutineDispatchers.main, "RoomScope-$roomId")
     private val _membersStateFlow = MutableStateFlow<MatrixRoomMembersState>(MatrixRoomMembersState.Unknown)
-    private val isInit = MutableStateFlow(false)
+    private val isInit = AtomicBoolean(false)
     private val _syncUpdateFlow = MutableStateFlow(0L)
     private val _timeline by lazy {
         RustMatrixTimeline(
@@ -107,7 +108,9 @@ class RustMatrixRoom(
     override val timeline: MatrixTimeline = _timeline
 
     override fun open(): Result<Unit> {
-        if (isInit.value) return Result.failure(IllegalStateException("Listener already registered"))
+        return if (isInit.getAndSet(true)) {
+            Result.failure(IllegalStateException("Listener already registered"))
+        } else {
             val settings = RoomSubscription(
                 requiredState = listOf(
                     RequiredState(key = EventType.STATE_ROOM_CANONICAL_ALIAS, value = ""),
@@ -135,13 +138,12 @@ class RustMatrixRoom(
 
                 fetchMembers()
             }
-        isInit.value = true
-        return Result.success(Unit)
+            Result.success(Unit)
+        }
     }
 
     override fun close() {
-        if (isInit.value) {
-            isInit.value = false
+        if (isInit.getAndSet(false)) {
             roomCoroutineScope.cancel()
             roomListItem.unsubscribe()
             innerRoom.destroy()