return (mBuffer.get() != GetSharedEmptyBufferHandle()) ? mBuffer->DataStart() : 0;
return (mBuffer->GetImplementationFlags() & shared_buffer_handle_type::kIsNULL) ? 0 : mBuffer->DataStart();
      virtual const char_type* get() const        {          return (mBuffer.get() != GetSharedEmptyBufferHandle())                    ? mBuffer->DataStart()                    : 0;        }