fetchMessagePart method
Fetches the part with the specified fetchId of the specified message.
This can be useful when you have specified an automatic download
limit with downloadSizeLimit in the MailClient's constructor and want to download an individual attachment, for example.
Note that this is only possible when the user is connected via IMAP and not via POP.
Compare lowLevelIncomingMailClientType.
Implementation
Future<MimePart> fetchMessagePart(MimeMessage message, String fetchId) {
return _incomingMailClient.fetchMessagePart(message, fetchId);
}