Function pdf_set_annot_appearance 

pub unsafe extern "C" fn pdf_set_annot_appearance(
    ctx: *mut fz_context,
    annot: *mut pdf_annot,
    appearance: *const c_char,
    state: *const c_char,
    ctm: fz_matrix,
    bbox: fz_rect,
    res: *mut pdf_obj,
    contents: *mut fz_buffer,
)