CheckEmails verifies that the provided email messages exist on the mock.

Tests that send emails should call Reset as part of their cleanup to ensure that other tests can depend on the state of the mock.

Emails contains all emails sent by the mock which tests can use to verify which emails were sent.

EmailLog combines email data with a mutex to ensure that tests can safely access the mock concurrently.

EmailMeta makes it easier for tests to verify that the correct emails were sent without comparing the entire email body.