anchor: Data:getFFIPointer
  Gets an FFI pointer to the Data.
  
  This function should be preferred instead of Data:getPointer because the latter uses light userdata which can't store more all possible memory addresses on some new ARM64 architectures, when LuaJIT is used.
  pointer = Data:getFFIPointer()
  pointer cdata A raw void* pointer to the Data, or nil if FFI is unavailable.