Make Loop and LoopData only hold move-only functions

src/Loop.h

@@ -110,25 +110,25 @@ public:
     }
 
     /* Set postCb callback */
-    void setPostHandler(std::function<void(Loop *)> handler) {
+    void setPostHandler(fu2::unique_function<void(Loop *)> &&handler) {
         LoopData *loopData = (LoopData *) us_loop_ext((us_loop *) this);
 
-        loopData->postHandler = handler;
+        loopData->postHandler = std::move(handler);
     }
 
-    void setPreHandler(std::function<void(Loop *)> handler) {
+    void setPreHandler(fu2::unique_function<void(Loop *)> &&handler) {
         LoopData *loopData = (LoopData *) us_loop_ext((us_loop *) this);
 
-        loopData->preHandler = handler;
+        loopData->preHandler = std::move(handler);
     }
 
     /* Defer this callback on Loop's thread of execution */
-    void defer(std::function<void()> cb) {
+    void defer(fu2::unique_function<void()> &&cb) {
         LoopData *loopData = (LoopData *) us_loop_ext((us_loop *) this);
 
         //if (std::thread::get_id() == ) // todo: add fast path for same thread id
         loopData->deferMutex.lock();
-        loopData->deferQueues[loopData->currentDeferQueue].emplace_back(cb);
+        loopData->deferQueues[loopData->currentDeferQueue].emplace_back(std::move(cb));
         loopData->deferMutex.unlock();
 
         us_wakeup_loop((us_loop *) this);

src/LoopData.h

@@ -25,6 +25,8 @@
 
 #include "PerMessageDeflate.h"
 
+#include "f2/function2.hpp"
+
 namespace uWS {
 
 struct Loop;
@@ -34,9 +36,9 @@ struct alignas(16) LoopData {
 private:
     std::mutex deferMutex;
     int currentDeferQueue = 0;
-    std::vector<std::function<void()>> deferQueues[2];
+    std::vector<fu2::unique_function<void()>> deferQueues[2];
 
-    std::function<void(Loop *)> postHandler, preHandler;
+    fu2::unique_function<void(Loop *)> postHandler, preHandler;
 
 public:
     ~LoopData() {