AdcGenericNetServer, AdcDeviceNetServer, AdcDeviceNetServer::Session and

AdcDeviceNetServerASIO classes now have template parameter 'IdentT' (type
of identificator)

common/adc_traits.h

@@ -270,4 +270,11 @@ using adc_common_duration_t = adc_duration_common_type_t<std::chrono::nanosecond
                                                          std::chrono::years>;
 
 
+// concept for hashable types
+template <typename T>
+concept adc_hashable_c = requires(T t) {
+    { std::hash<T>{}(t) } -> std::convertible_to<std::size_t>;
+};
+
+
 }  // namespace adc::traits