redo packet build/parse

now with evbuffer

src/util.cpp

@@ -15,6 +15,7 @@
 
 #include <pvxs/util.h>
 #include "utilpvt.h"
+#include "udp_collector.h"
 
 namespace pvxs {
 
@@ -30,6 +31,12 @@ unsigned long version_int()
     return PVXS_VERSION;
 }
 
+void cleanup_for_valgrind()
+{
+    pvxsimpl::logger_shutdown();
+    pvxsimpl::UDPManager::cleanup();
+}
+
 namespace detail {
 
 std::ostream& operator<<(std::ostream& strm, const Escaper& esc)