proc to_uint32(self: seq[uint8]): uint32 =
  if self.len() != 4:
    return 0
  result = (cast[uint32](self[3]) shl 0) or
          (cast[uint32](self[2]) shl 8) or
          (cast[uint32](self[1]) shl 16) or
          (cast[uint32](self[0]) shl 24)

proc to_uint8_seq(self: uint32): seq[uint8] =
  result = @[]
  result.add(cast[uint8](self shr 0))
  result.add(cast[uint8](self shr 8))
  result.add(cast[uint8](self shr 16))
  result.add(cast[uint8](self shr 24))

when isMainModule:
  let sample = @[0x00'u8, 0x00, 0x00, 0x10]
  echo sample.to_uint32()                    # 16
  echo sample.to_uint32().to_uint8_seq()    # @[0, 0, 0, 16]