maven replace regex replacement leading whitespace

I'm doing some replaceRegex rules and I'm attempting to replace some text with `` { }`` however the leading whitespace gets trimmed and doesn't get added.

I've tried numerous work arounds using unicode, cdata, escape codes, and they all get trimmed (or the formatter just breaks)

How the heck do i add a leading space in the replacement text?

```xml

collapseEmptyBlocks
(?s)[\s\r\n]*\{[\s\r\n]*\}
{}

```