Make VRS libray better compile on Windows

Summary: Our Windows compiler is particularly unhappy about unused arguments, making them not unused in the most compiler- and linter-friendly way.

Reviewed By: georges-berenger

Differential Revision: D51550307

fbshipit-source-id: f7ffeb173f509c178bc9a558d99d68d9b47d9b73

vrs/FileDelegator.h

@@ -58,6 +58,7 @@ class FileDelegator {
   /// exists or can be opened, merely, that parsing the URI did not fail.
   /// On success, any of the fields may have been set or changed, including fileHandlerName and URI.
   virtual int parseUri(FileSpec& inOutFileSpec, size_t colonIndex) const {
+    (void)colonIndex;
     return inOutFileSpec.parseUri();
   }
 };

vrs/FileHandler.h

@@ -136,6 +136,7 @@ class FileHandler : public FileDelegator {
   /// @param length: the number of bytes to check availability of.
   /// @return true if available, false if unavailable (e.g. requiring a network fetch)
   virtual bool isAvailableOrPrefetch(size_t length) {
+    (void)length;
     return !isRemoteFileSystem();
   }
   /// Read a number of bytes, in a chunk aware way.
@@ -211,6 +212,8 @@ class FileHandler : public FileDelegator {
   virtual bool prefetchReadSequence(
       const vector<std::pair<size_t, size_t>>& sequence,
       bool clearSequence = true) {
+    (void)sequence;
+    (void)clearSequence;
     return false;
   }