func consume(v: var BytesView; n: int) {.inline, ...raises: [], tags: [],
    forbids: [].}

proc init(t: typedesc[BytesView]; data: sink seq[byte]): BytesView

func len(v: BytesView): int {.inline, ...raises: [], tags: [], forbids: [].}

template data(v: BytesView): openArray[byte]

template toOpenArray(v: BytesView; b, e: int): openArray[byte]