This table has the same structure than mail. When a message is trashed, it is moved
from mail into trashed_mail to help reduce the size of
the main mail table. Every row in trashed_mail should have the
Trashed bit set in its status field. In other words, the
condition status&16=16 should always be true for every row in this
table. Symmetrically, the condition status&16=16 should never be true
for rows in the mail table.