Function get_blockchain_parameters_packed 

pub unsafe extern "C" fn get_blockchain_parameters_packed(
    data: *mut c_char,
    datalen: u32,
) -> u32

@brief Retrieve the blolckchain parameters Retrieve the blolckchain parameters @param data - output buffer of the blockchain parameters, only retrieved if sufficent size to hold packed data. @param datalen - size of the data buffer, 0 to report required size. @return size of the blockchain parameters @pre data is a valid pointer to a range of memory at least datalen bytes long @post data is filled with packed blockchain parameters