Add JK to enable/disable rate limiting based on NIC

Summary: As title, to disable ARL based on NIC quickly, given the nature of counters

Reviewed By: kwaugh

Differential Revision: D100241433

fbshipit-source-id: 32b076f843cd0382cfadfee2048194114b0ffcd2

Author: Oleksandr Yermolenko

eden/mononoke/common/adaptive_rate_limiter/BUCK

@@ -12,7 +12,9 @@ cpp_library(
         "src/ffi.h",
     ],
     undefined_symbols = True,
-    deps = [],
+    deps = [
+        "//folly:singleton",
+    ],
     exported_deps = [
         "//eden/mononoke/common/adaptive_rate_limiter/cpp:adaptive_rate_limiter_cpp",
     ],

eden/mononoke/common/adaptive_rate_limiter/src/ffi.cpp

@@ -7,10 +7,17 @@
 
 #include "eden/mononoke/common/adaptive_rate_limiter/src/ffi.h"
 
+#include <folly/Singleton.h>
+
 namespace facebook::mononoke::ffi {
 
 std::unique_ptr<CppAdaptiveRateLimiterWrapper> new_adaptive_rate_limiter(
     const CppAdaptiveRateLimiterConfig& config) {
+  // Ensure folly singletons are initialized. Idempotent — no-op if
+  // folly::init was already called (e.g., in production revproxy).
+  // Required for non-folly binaries (Rust tests) where C++ static
+  // destructors may access singletons like JustKnobs.
+  folly::SingletonVault::singleton()->registrationComplete();
   return std::make_unique<CppAdaptiveRateLimiterWrapper>(config);
 }