Switch AutoTimer looging to fmt::format

Summary: Switch AutoTimer looging to fmt::format

Reviewed By: mpark

Differential Revision: D31980311

fbshipit-source-id: 91e819a169a16540984e503f7562f9c2d36f75db

folly/experimental/AutoTimer.h

@@ -98,7 +98,7 @@ class AutoTimer final {
   template <typename... Args>
   DoubleSeconds logFormat(Args&&... args) {
     auto now = Clock::now();
-    return logImpl(now, format(std::forward<Args>(args)...).str());
+    return logImpl(now, fmt::format(std::forward<Args>(args)...));
   }
 
  private: