Task:

1. Start with open IMAP inbox (~1,000 messages), threaded.
2. Begin profile.
3. Switch to IMAP sent folder (~2,000 messages), unthreaded.
4. End profile.

Should collect:

- teardown cost of Inbox content model
- setup cost of sent content model

Profile shows:

All CPU time spent on main thread (1542msec).

  - 28% of the time (432msec) spent in two calls to
    nsXULDocument::RebuildWidgetItem()

    - 34% of this time (147msec) spent in
      XULSortServiceImpl::InsertContainerNode(), inserting nodes into
      the content model. This is dominated by the sorting routines.

    - 16% of this time (68msec) spent in
      nsMessageViewEnumerator::HasMoreElements(), reading the RDF
      container.

    - 9% of the time (38msec) is spent in 4,200 calls to
      nsXULElement::SetAttribute(). This is dominated by attribute
      creation cost.

    - 7% of this time (32msec) spent in
      InstantiationNode::Propogate(), which is purely
      nsXULTemplateBuilder overhead

    - 5% of the time (20msec) spent creating nsXULElement::Create()
      and nsXULElement::EnsureSlots(), in other words, making content
      elements.

  - 18% of the time (277msec) spent in three calls to
    PresShell::ProcessReflowCommands()

  - 14% of the time (201msec) spent in one call to nsMsgDatabase::OpenMDB()

  - 12% of the time (173msec) spent in 157 calls to nsWindow::OnPaint()

  - 5% of the time (77msec) spent in 126 miscellaneous SetAttribute()
    calls (triggers style re-resolve, etc.)

  - 4% of the time (68msec) spent in one call to
    nsImapFolder::UpdateImapMailboxInfo()

  - 3% of the time (62msec) spent in two calls to SetContentState(),
    triggering reflows from two focus changes.

  - 3% of the teme (48msec) spent in IMAP synchronization primitives
    (LeaveCriticalSection, ReleaseSemaphore).

  - 13% unaccounted time.