split abstract method
Splits this sequence of characters at each occurrence of pattern.
Returns a lazy iterable of characters that were separated by pattern.
The iterable has at most maxParts elements if a positive maxParts
is supplied.
Finds each occurrence of pattern, which does not overlap with
a previously found occurrence, then the non-matched characters
before, after, and between the matches are provided in first-to-last
position order.
If pattern is empty, the character sequence is split into separate
characters, and no leading or trailing empty ranges are provided
unless the range itself is empty,
in which case a single empty range is the only result range.
Otherwise a range starting or ending with pattern will cause
an empty character sequence to be emitted at the start or end.
If maxParts is provided and greater than zero,
only the first maxParts - 1 occurrences of pattern are found
and split at.
Any further occurrences will be included in the last part.
Example:
var c = 'abracadabra'.characters;
var parts = c.split('a'.characters, 4).toList();
print(parts); // Prints is ['', 'br', 'c', 'dabra']
If there are fewer than maxParts - 1 occurrences of pattern,
then the characters are split at all occurrences.
If maxParts is zero or negative, it is ignored and the result
is split at all occurrences of pattern.
Implementation
/// If [pattern] is empty, the character sequence is split into separate
/// characters, and no leading or trailing empty ranges are provided
/// unless the range itself is empty,
/// in which case a single empty range is the only result range.
/// Otherwise a range starting or ending with [pattern] will cause
/// an empty character sequence to be emitted at the start or end.
///
/// If [maxParts] is provided and greater than zero,
/// only the first `maxParts - 1` occurrences of [pattern] are found
/// and split at.
/// Any further occurrences will be included in the last part.
/// Example:
/// ```dart
/// var c = 'abracadabra'.characters;
/// var parts = c.split('a'.characters, 4).toList();
/// print(parts); // Prints is ['', 'br', 'c', 'dabra']
/// ```
/// If there are fewer than `maxParts - 1` occurrences of [pattern],
/// then the characters are split at all occurrences.
/// If [maxParts] is zero or negative, it is ignored and the result
/// is split at all occurrences of [pattern].
Iterable<Characters> split(Characters pattern, [int maxParts = 0]);