The leading space that is always printed at the beginning of regions is not consistent with other parts of the printing API. Moreover, this leading space can lead to undesirable assembly formats:
attr-dict-with-keyword $region
Prints as:
// Two spaces between `}` and `{` attributes {foo} { ... }
Moreover, the leading space results in the odd generic op format:
"test.op"() ( {...}) : () -> ()