header.go
func (h *RequestHeader) SetBytesV(key string, value []byte) {
	k := getHeaderKeyBytes(&h.bufKV, key, h.disableNormalizing)
	h.SetCanonical(k, value)
}
func (h *RequestHeader) SetBytesV(key string, value []byte) {
	k := getHeaderKeyBytes(&h.bufKV, key, h.disableNormalizing)
	h.SetCanonical(k, value)
}
// SetBytesV sets the given 'key: value' header.
//
// Use AddBytesV for setting multiple header values under the same key.