LineSplitter class Null safety

A StreamTransformer that splits a String into individual lines.

A line is terminated by either:

• a CR, carriage return: U+000D ('\r')
• a LF, line feed (Unix line break): U+000A ('\n') or
• a CR+LF sequence (DOS/Windows line break), and
• a final non-empty line can be ended by the end of the input.

The resulting lines do not contain the line terminators.

Example:

const splitter = LineSplitter();
const sampleText =
    'Dart is: \r an object-oriented \n class-based \n garbage-collected '
    '\r\n language with C-style syntax \r\n';

final sampleTextLines = splitter.convert(sampleText);
for (var i = 0; i < sampleTextLines.length; i++) {
  print('$i: ${sampleTextLines[i]}');
}
// 0: Dart is:
// 1:  an object-oriented
// 2:  class-based
// 3:  garbage-collected
// 4:  language with C-style syntax