createHeadersFromArray function
Creates Headers from array of 2 items arrays.
Implementation
Headers createHeadersFromArray(List<List<String>> init) {
final _init = JsArray<JsArray<dynamic>>();
for (final header in init) {
if (header.length != 2)
throw Exception('Bad argument');
_init.add(header.toJsArray());
}
return Headers._init(_init);
}