adds a mutex to make sure memory clearing only happens once at a time.

amethyst/src/main/java/com/vitorpamplona/amethyst/ServiceManager.kt

@@ -71,6 +71,7 @@ import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.runBlocking
+import java.util.concurrent.atomic.AtomicBoolean
 
 @Stable
 class ServiceManager(
@@ -84,6 +85,8 @@ class ServiceManager(
 
     private var collectorJob: Job? = null
 
+    var isTrimmingMemoryMutex = AtomicBoolean(false)
+
     private fun start(account: Account) {
         this.account = account
         start()
@@ -259,6 +262,8 @@ class ServiceManager(
     }
 
     suspend fun trimMemory() {
+        if (isTrimmingMemoryMutex.compareAndSet(false, true)) {
+            try {
                 LocalCache.cleanObservers()
 
                 val accounts =
@@ -274,6 +279,10 @@ class ServiceManager(
                     LocalCache.prunePastVersionsOfReplaceables()
                     LocalCache.pruneExpiredEvents()
                 }
+            } finally {
+                isTrimmingMemoryMutex.getAndSet(false)
+            }
+        }
     }
 
     // This method keeps the pause/start in a Syncronized block to