adding api to get number of matched reader/writers (#9)

Co-authored-by: Alexandru Kampmann <kampmann@embedded.rwth-aachen.de>

Author: akampmann

include/rtps/entities/Reader.h

@@ -98,6 +98,8 @@ class Reader {
     return false;
   }
 
+  uint32_t getNumMatchedWriters() { return m_proxies.getSize(); }
+
 protected:
   bool m_is_initialized_ = false;
   virtual ~Reader() = default;

include/rtps/entities/Writer.h

@@ -52,6 +52,8 @@ class Writer {
 
   bool isInitialized() { return m_is_initialized_; }
 
+  uint32_t getNumMatchedReader(){ return m_proxies.getSize();}
+
 protected:
   bool m_is_initialized_ = false;
   virtual ~Writer() = default;