Remove RSocket

Summary:
^
Changelog: Remove rsocket references from xplat

Reviewed By: aigoncharov

Differential Revision: D34418118

fbshipit-source-id: bd49b9da119e3a2a1ce396d14e0dca73e1b9c692

xplat/Flipper/FlipperSocketProvider.h

@@ -66,15 +66,7 @@ class FlipperSocketProvider {
   static void setDefaultProvider(
       std::unique_ptr<FlipperSocketProvider> provider);
 
-  /**
-    Shelves the current default socket provider and promotes the internal
-    socket provider as default.
-   */
-  static void shelveDefault();
-  /**
-    Restores a previously shelved socket provider.
-   */
-  static void unshelveDefault();
+  static bool hasProvider();
 
  private:
   static std::unique_ptr<FlipperSocketProvider> provider_;