public static FastStr of(Iterable<Character> itr) {
        StringBuilder sb = new StringBuilder();
        for (Character c : itr) {
            sb.append(c);
        }
        return of(sb);
    }
public static FastStr of ( Iterable < Character > itr ) { StringBuilder sb = new StringBuilder ( ) ; for ( Character c : itr ) { sb . append ( c ) ; } return of ( sb ) ; }
Construct a FastStr instance from an iterable of characters
@param itr the character iterable
@return the FastStr