SendToAdmins sends an email message to the application's administrators.
Attachment
typeAttachmentstruct{// Name must be set to a valid file name.NamestringData[]byteContentIDstring}
An Attachment represents an email attachment.
Message
typeMessagestruct{// Sender must be set, and must be either an application admin// or the currently signed-in user.SenderstringReplyTostring// may be empty// At least one of these slices must have a non-zero length,// except when calling SendToAdmins.To,Cc,Bcc[]stringSubjectstring// At least one of Body or HTMLBody must be non-empty.BodystringHTMLBodystringAttachments[]Attachment// Extra mail headers.// See https://cloud.google.com/appengine/docs/standard/go/mail/// for permissible headers.Headersmail.Header}
A Message represents an email message.
Addresses may be of any form permitted by RFC 822.