fix warning

include/sp/protocol/message/OstreamFieldIterator.h

@@ -3,23 +3,29 @@
 // Lifted from Jerry Coffin's 's prefix_ostream_iterator
 #pragma once
 
-#include <iterator>
 #include <ostream>
 #include <sp/protocol/Field.h>
 
 namespace sp {
 
 template <class T, class charT = char, class traits = std::char_traits<charT>>
-class OstreamFieldIterator : public std::iterator<std::output_iterator_tag, void, void, void, void> {
+class OstreamFieldIterator {
   private:
 	std::basic_ostream<charT, traits>* m_Os;
 	std::string m_Delimiter;
 	bool m_FirstElem;
 
   public:
-	typedef charT char_type;
-	typedef traits traits_type;
-	typedef std::basic_ostream<charT, traits> ostream_type;
+	using iterator_category = std::output_iterator_tag;
+	using value_type = void;
+	using difference_type = void;
+	using pointer = void;
+	using reference = void;
+
+	using char_type = charT;
+	using traits_type = traits;
+	using ostream_type = std::basic_ostream<charT, traits>;
+
 	OstreamFieldIterator(ostream_type& a_Stream) : m_Os(&a_Stream), m_Delimiter(0), m_FirstElem(true) {}
 	OstreamFieldIterator(ostream_type& a_Stream, std::string&& a_Delimiter) :
 		m_Os(&a_Stream), m_Delimiter(std::move(a_Delimiter)), m_FirstElem(true) {}