typedef int (*rpc_exec_write_cb_t)(struct ustream *, void *);
typedef int (*rpc_exec_read_cb_t)(struct blob_buf *, char *, int, void *);
typedef int (*rpc_exec_write_cb_t)(struct ustream *, void *);
typedef int (*rpc_exec_read_cb_t)(struct blob_buf *, char *, int, void *);