Comment 11 for bug 1052306

from one of the crashes, this is the call site:

http://hg.mozilla.org/releases/comm-release/annotate/6ccee99d387c/mailnews/imap/src/nsImapProtocol.cpp#l1602

Since we're checking for m_imapMailFolderSink is null before calling this, we might have some sort of race condition, if I'm understanding the crash info correctly.