Function croaring_sys::roaring_bitmap_portable_deserialize_size

pub unsafe extern "C" fn roaring_bitmap_portable_deserialize_size(
    buf: *const c_char,
    maxbytes: usize
) -> usize

Check how many bytes would be read (up to maxbytes) at this pointer if there is a bitmap, returns zero if there is no valid bitmap.

This is meant to be compatible with the Java and Go versions: https://github.com/RoaringBitmap/RoaringFormatSpec