int sd_bus_message_append_array_iovec(sd_bus_message *m, char type, const struct iovec *iov, unsigned n);
int sd_bus_message_append_array_memfd(sd_bus_message *m, char type, int memfd, uint64_t offset, uint64_t size);
int sd_bus_message_append_string_space(sd_bus_message *m, size_t size, char **s);
int sd_bus_message_append_array_iovec(sd_bus_message *m, char type, const struct iovec *iov, unsigned n);
int sd_bus_message_append_array_memfd(sd_bus_message *m, char type, int memfd, uint64_t offset, uint64_t size);
int sd_bus_message_append_string_space(sd_bus_message *m, size_t size, char **s);