addFlag method
Adds the flag with the specified name
to this message.
Note that this only affects this message instance and is not persisted or reported to the mail service automatically.
Implementation
void addFlag(String name) {
final mimeFlags = flags;
if (mimeFlags == null) {
flags = [name];
} else if (!mimeFlags.contains(name)) {
mimeFlags.add(name);
}
}