Use std::destroy_at instead of manually calling the destructor

Ideally the construction should also use std::construct_at instead of a
placement new but this would require C++20

include/pistache/async.h

@@ -250,7 +250,7 @@ namespace Pistache::Async
 
                 if (allocated)
                 {
-                    reinterpret_cast<T*>(mem)->~T();
+                    std::destroy_at(reinterpret_cast<T*>(mem));
                     allocated = false;
                 }
 
@@ -274,7 +274,7 @@ namespace Pistache::Async
             {
                 if (allocated)
                 {
-                    reinterpret_cast<T*>(&storage)->~T();
+                    std::destroy_at(reinterpret_cast<T*>(storage));
                     allocated = false;
                 }
             }

include/pistache/mailbox.h

@@ -213,8 +213,7 @@ namespace Pistache
             T& data() { return *reinterpret_cast<T*>(&storage); }
 
         private:
-            typedef typename std::aligned_storage<sizeof(T), alignof(T)>::type Storage;
-            Storage storage;
+            alignas(T) std::byte storage[sizeof(T)];
             std::atomic<Entry*> next;
         };
 
@@ -233,7 +232,7 @@ namespace Pistache
             while (!empty())
             {
                 Entry* e = pop();
-                e->data().~T();
+                std::destroy_at(&e->data());
                 delete e;
             }
             delete tail;
@@ -258,7 +257,7 @@ namespace Pistache
                 // Since it's Single-Consumer, the store does not need to be atomic
                 tail = next;
                 new (&res->storage) T(std::move(next->data()));
-                next->data().~T();
+                std::destroy_at(&next->data());
                 return res;
             }
             return nullptr;
@@ -275,7 +274,7 @@ namespace Pistache
             if (entry)
             {
                 object.reset(new T(std::move(entry->data())));
-                entry->data().~T();
+                std::destroy_at(&entry->data());
             }
 
             return object;