xargs: add support for -E option

[brian-pane]

No description provided.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.69%. Comparing base (0f7bf4d) to head (2e74005).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #593      +/-   ##
==========================================
+ Coverage   88.88%   91.69%   +2.81%     
==========================================
  Files          31       31              
  Lines        6297     6179     -118     
  Branches      324      327       +3     
==========================================
+ Hits         5597     5666      +69     
+ Misses        578      392     -186     
+ Partials      122      121       -1     

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[brian-pane]

I'll add more test coverage and post an update.

[cakebaker]

I think you can simplify the code a bit by using map. Something like:

Suggested change

	match self.reader.next() {
	Err(e) => Err(e),
	Ok(arg) => match arg {
	None => Ok(None),
	Some(arg) => {
	if arg.arg == self.eof_delimiter {
	Ok(None)
	} else {
	Ok(Some(arg))
	}
	}
	},
	}
	self.reader.next().map(|opt| {
	opt.and_then(|arg| {
	if arg.arg == self.eof_delimiter {
	None
	} else {
	Some(arg)
	}
	})
	})

[cakebaker]

Thanks for your PR!