Added class DrivenEngine (no implementation yet)

luprex/core/cpp/streambuffer.hpp

@@ -259,6 +259,9 @@ public:
     // Amount of data inside the buffer.
     int64_t fill() const;
     
+    // Get a pointer to the data.
+    const char *data() const;
+    
     // Discard all data.  Reset total read and write counts.
     // Frees up as much space as possible.
     void clear();