From Wang Rui, "I'd like to submit the changes that will put ObjectProperty and ObjectMark variables into the InputStream/OutputStream class instead of static ones. This should avoid the threading problem and won't repeatedly reallocate memory for the properties. Some of the wrappers will be slightly modified to use the property variable stored in the InputStream/OutputStream as well."

include/osgDB/OutputStream

@@ -164,6 +164,11 @@ public:
     inline void throwException( const std::string& msg );
     const OutputException* getException() const { return _exception.get(); }
 
+    // Property & mask variables
+    ObjectProperty PROPERTY;
+    ObjectMark BEGIN_BRACKET;
+    ObjectMark END_BRACKET;
+
 protected:
     template<typename T>
     void writeArrayImplementation( const T*, int write_size, unsigned int numInRow=1 );