Net::IMAP::MailboxQuota represents contents of GETQUOTA response.
This object can also be a response to GETQUOTAROOT.  In the syntax
specification below, the delimiter used with the "#" construct is a
single space (SPACE).

   quota_list      ::= "(" #quota_resource ")"

   quota_resource  ::= atom SPACE number SPACE number

   quota_response  ::= "QUOTA" SPACE astring SPACE quota_list