ids
<link rel="help" href="https://w3c.github.io/webvtt/#collect-a-webvtt-block">

assert_equals(cues.length, 5);
assert_equals(cues[0].id, " leading space");
assert_equals(cues[1].id, "trailing space ");
assert_equals(cues[2].id, "-- >");
assert_equals(cues[3].id, "->");
assert_equals(cues[4].id, " ");

===
WEBVTT

\x20leading space
00:00:00.000 --> 00:00:01.000
text0

trailing space\x20
00:00:00.000 --> 00:00:01.000
text1

-- >
00:00:00.000 --> 00:00:01.000
text2

->
00:00:00.000 --> 00:00:01.000
text3

\x20
00:00:00.000 --> 00:00:01.000
text4