Add fix for index out of bounds during high load

src/invidious/helpers/handlers.cr

@@ -237,3 +237,16 @@ class HTTP::Client
     response
   end
 end
+
+struct Crystal::ThreadLocalValue(T)
+  @values = Hash(Thread, T).new
+
+  def get(&block : -> T)
+    th = Thread.current
+    if !@values[th]?
+      @values[th] = yield
+    else
+      @values[th]
+    end
+  end
+end