LittleFS: add overrides for Stream::send (#8386)

* littlefs: add overrides for Stream::send

cores/esp8266/FS.h

@@ -118,6 +118,18 @@ public:
     time_t getCreationTime();
     void setTimeCallback(time_t (*cb)(void));
 
+    // Stream::send configuration
+
+    bool inputCanTimeout () override {
+        // unavailable data can't become later available
+        return false;
+    }
+
+    bool outputCanTimeout () override {
+        // free space for write can't increase later
+        return false;
+    }
+
 protected:
     FileImplPtr _p;
     time_t (*_timeCallback)(void) = nullptr;