The Delimiters String can have more than one character for a delimiter.
When the index is 1 and the delimiter is empty, or not found, the full source string will return.
An empty string is returned when a delimiter is not found (empty delimiter, out of range index, or not exist delimiter), and the index is more than 1.
Every delimiter will be counted for the index calculation (no repetition).
A space cannot be a delimiter.