code: public Set<MailAccount> getReservedMailAccountsForCurrentThread() {
  		lock.lock();
  		try {
  			Map<MailAccount, ThreadReservationKeyWrapper> accountsForThread = filterValues(usedAccounts, new CurrentThreadWrapperPredicate());
  			return ImmutableSet.copyOf(accountsForThread.keySet());
  		} finally {
  			lock.unlock();
  		}
  	}
docs: Gets the set of reserved mail accounts for the current thread.
  
  @return the set of reserved mail accounts