Sets the bulk priority (0-9, lower = higher priority).
Enables embedding all attachments in the HTML body.
Returns any accumulated error messages.
Sets the priority. Positive = high, zero = normal, negative = low.
Clears accumulated errors.
Validates and queues the email for sending. Returns true on success, false on validation failure.
A chainable email builder compatible with the legacy newEmail() formula. Build an email by chaining method calls, then call send() to queue for delivery.