ffi_demo: add vtmodel part, add 0 terminator byte to pickle size
ffi_demo: add vtmodel part, add 0 terminator byte to pickle size

SKA-ScienceDataProcessor/algorithm-reference-library,SKA-ScienceDataProcessor/algorithm-reference-library,SKA-ScienceDataProcessor/algorithm-reference-library,SKA-ScienceDataProcessor/algorithm-reference-library,SKA-ScienceDataProcessor/algorithm-reference-library