-n should always effected no matter using text or file source

[Albin Sun]

msg: generator iter all file contents (if file) or infinite iteration (if msg)
runs: control number of submission

• -n default is None, negative for infinite
• behavior

-n \ src	file	msg
None (default)	infinite	send 1
N (>=0)	send N	send N
N (< 0)	infinite	infinite

if msg and args.number is None: args.number = 1
runs = N runs if args.number >= 0 else infinite runs