 match limit
  Change the backtracking depth limit
  Set custom memory management specifically for the match
</pre>
The <i>length</i> and <i>startoffset</i> values are code units, not characters.
The length may be given as PCRE2_ZERO_TERMINATED for a subject that is
terminated by a binary zero code unit. The options are:
<pre>
  PCRE2_ANCHORED          Match only at the first position
  PCRE2_COPY_MATCHED_SUBJECT
                          On success, make a private subject copy
  PCRE2_ENDANCHORED       Pat