Replace the first occurrence of from in this string.
Returns a new string, which is this string
except that the first match of from, starting from startIndex,
is replaced by the result of calling replace with the match object.
The optional startIndex is by default set to 0. If provided, it must be
an integer in the range [0 .. len], where len is this string's length.
If the value returned by calling replace is not a String, it
is converted to a String using its toString method, which must
then return a string.
Source
String replaceFirstMapped(Pattern from, String replace(Match match),
[int startIndex = 0]);