Multipart.heads.found: def of bend-kit-multipart@0.3.0.0
Import: import bend-kit-multipart@0.3.0.0/multipart.bend as Multipart
Lines 510-517 of bend-kit-multipart@0.3.0.0/multipart.bend: https://jend.leeeet.dev/read.txt?path=bend-kit-multipart@0.3.0.0/multipart.bend&start_line=510&end_line=517

import Base
import bend-kit-bytes@0.3.3.0/bytes.bend as Bytes

# buf starts with the CRLF that ended the boundary line, so a match at 0 is an empty block.
def heads.found(r: Bytes.Bytes & Maybe<&2, U32>, out: List<&1, Item>) -> Step:
  (buf, hit) = r
  match hit:
    case Some{+j}:
      heads.cut(j, Bytes.slice(buf, 2, (U32.max(j, 2) - 2 : U32)), out)
    case None{}:
      wait.big(Heads{}, Bytes.length(buf), out)

Uses (15):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Sigma
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.max
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=U32.sub
  https://jend.leeeet.dev/definition.txt?path=bend-kit-bytes@0.3.3.0/bytes.bend&name=Bytes
  https://jend.leeeet.dev/definition.txt?path=bend-kit-bytes@0.3.3.0/bytes.bend&name=length
  https://jend.leeeet.dev/definition.txt?path=bend-kit-bytes@0.3.3.0/bytes.bend&name=slice
  https://jend.leeeet.dev/definition.txt?path=bend-kit-multipart@0.3.0.0/multipart.bend&name=Item
  https://jend.leeeet.dev/definition.txt?path=bend-kit-multipart@0.3.0.0/multipart.bend&name=Stage
  https://jend.leeeet.dev/definition.txt?path=bend-kit-multipart@0.3.0.0/multipart.bend&name=Step
  https://jend.leeeet.dev/definition.txt?path=bend-kit-multipart@0.3.0.0/multipart.bend&name=heads.cut
  https://jend.leeeet.dev/definition.txt?path=bend-kit-multipart@0.3.0.0/multipart.bend&name=wait.big