enlarge filesystem buffer

lib_standalone/FSPersistence.h

@@ -12,7 +12,7 @@ class FSPersistence {
                   StatefulService<T> * statefulService,
                   FS *                 fs,
                   const char *         filePath,
-                  size_t               bufferSize = DEFAULT_BUFFER_SIZE)
+                  size_t               bufferSize = FS_BUFFER_SIZE)
         : _stateReader(stateReader)
         , _stateUpdater(stateUpdater)
         , _statefulService(statefulService)

lib_standalone/StatefulService.h

@@ -11,6 +11,10 @@
 #define DEFAULT_BUFFER_SIZE 2048
 #endif
 
+#ifndef FS_BUFFER_SIZE
+#define FS_BUFFER_SIZE 4096
+#endif
+
 enum class StateUpdateResult {
     CHANGED = 0, // The update changed the state and propagation should take place if required
     UNCHANGED,   // The state was unchanged, propagation should not take place