Function xmlShellDu 

#[unsafe(no_mangle)]
pub unsafe extern "C" fn xmlShellDu(
    ctxt: *mut _xmlShellCtxt,
    _arg: *mut c_char,
    tree: *mut _xmlNode,
    _node2: *mut _xmlNode,
) -> c_int

int xmlShellDu(xmlShellCtxtPtr ctxt, char *arg, xmlNodePtr tree, xmlNodePtr node2) — the shell “du” command: show the structure of the subtree under tree, deep-first.