set method
Implementation
void set(String name, dynamic value) {
final key = name.toLowerCase();
if (value is String) {
_headers[key] = [value];
} else if (value is List<String>) {
_headers[key] = List.from(value);
} else if (value is List) {
_headers[key] = value.map((v) => v.toString()).toList();
} else {
_headers[key] = [value.toString()];
}
}