def hdr.sum
import bend-kit-tar@0.3.0.0/tar.bend as Tarimport Base
import bend-kit-bytes@0.3.3.0/bytes.bend as Bytes
361def hdr.sum(+len: U32, +i: U32, r: Array<U32> & U32) -> Bytes.Bytes & Maybe<&2, Hdr>:
362 (a, +sum) = r
363 hdr.zero(U32.is_eq(sum, 0), len, i, sum, a)