Function libgit2_sys::git_diff_foreach

pub unsafe extern fn git_diff_foreach(diff: *mut git_diff,
                                      file_cb: git_diff_file_cb,
                                      binary_cb: Option<git_diff_binary_cb>,
                                      hunk_cb: Option<git_diff_hunk_cb>,
                                      line_cb: Option<git_diff_line_cb>,
                                      payload: *mut c_void)
                                      -> c_int