pub unsafe extern "C" fn fstReaderIterBlocks2(
ctx: *mut c_void,
value_change_callback: Option<unsafe extern "C" fn(user_callback_data_pointer: *mut c_void, time: u64, facidx: fstHandle, value: *const c_uchar)>,
value_change_callback_varlen: Option<unsafe extern "C" fn(user_callback_data_pointer: *mut c_void, time: u64, facidx: fstHandle, value: *const c_uchar, len: u32)>,
user_callback_data_pointer: *mut c_void,
vcdhandle: *mut FILE,
) -> c_int