Function left_pad_vec_be 

pub fn left_pad_vec_be(data: &[u8], len: usize) -> Cow<'_, [u8]>

Available on crate feature evm only.

Left-pads the given big-endian slice with zeroes until len.

Unlike left_pad_vec, when data is longer than len this correctly truncates leading (most-significant) bytes instead of trailing ones.