@Nonnull
		Matcher matcher(@Nonnull String input) {
			ThreadLocal<Matcher> tlc = this.matcher;
			Matcher matcher = tlc.get();
			if (matcher == null) {
				matcher = pattern.matcher(input);
				tlc.set(matcher);
			} else {
				matcher.flush();
				matcher.setTarget(input);
			}
			return matcher;
		}
@param regex
		Regular expression to compile.

@return Compiled pattern, or {@link #INVALID_PATTERN} if the pattern is invalid.
recaf-core/src/main/java/software/coley/recaf/util/RegexUtil.java