Anyone care to shed some light on why UITableView makes so many repeat calls to its delegate & datasource as it's being setup? Just looking at one I'm working on now I see that `numberOfSectionsInTableView` is called 3 times and then `viewForHeaderInSection` cycles through 3 more times for *each* section (I have 2 sections so total of 6 times before being displayed for first time)...all before the first screen is even rendered.

I realize that the API is *private* but wondering if someone might be willing to offer up some insight into this **design pattern** and what *might* be going on behind the scenes so I might learn a thing or two about why so much repetition is considered acceptable (or even advantageous) in this case...or, more likely, how I've managed to foul up applying it.

Edit: Added stack traces before RootViewController tableView is shown for first time

**1st time calling viewForHeaderInSection:**

```
#0  0x000086cc in -[RootViewController tableView:viewForHeaderInSection:] at RootViewController.m:444
#1  0x30c901a8 in -[UITableView(UITableViewInternal) _delegateWantsHeaderForSection:]
#2  0x30c8f6f4 in -[UISectionRowData refreshWithSection:tableView:tableViewRowData:]
#3  0x30c8f5a8 in -[UITableViewRowData rectForFooterInSection:]
#4  0x30c3d430 in -[UITableViewRowData heightForTable]
#5  0x30c05430 in -[UITableView(_UITableViewPrivate) _updateContentSize]
#6  0x30c3ce0c in -[UITableView noteNumberOfRowsChanged]
#7  0x30c3c7c0 in -[UITableView reloadData]
#8  0x30e50e60 in -[UITableViewController viewWillAppear:]
#9  0x30c78810 in -[UINavigationController _startTransition:fromViewController:toViewController:]
#10 0x30c783b0 in -[UINavigationController _startDeferredTransitionIfNeeded]
#11 0x30c782a0 in -[UINavigationController viewWillLayoutSubviews]
#12 0x30c5c874 in -[UILayoutContainerView layoutSubviews]
#13 0x30c382d8 in -[UIView(CALayerDelegate) _layoutSublayersOfLayer:]
#14 0x33e871c0 in -[CALayer layoutSublayers]
#15 0x33e86edc in CALayerLayoutIfNeeded
#16 0x33e86844 in CA::Context::commit_transaction
#17 0x33e86474 in CA::Transaction::commit
#18 0x33e8e5dc in CA::Transaction::observer_callback
#19 0x32d5c830 in __CFRunLoopDoObservers
#20 0x32da4346 in CFRunLoopRunSpecific
#21 0x32da3c1e in CFRunLoopRunInMode
#22 0x31bb9374 in GSEventRunModal
#23 0x30bf3c30 in -[UIApplication _run]
#24 0x30bf2230 in UIApplicationMain
#25 0x00002260 in main at main.m:14

```

**2nd call:**

```
#0  0x000086cc in -[RootViewController tableView:viewForHeaderInSection:] at RootViewController.m:444
#1  0x30c901a8 in -[UITableView(UITableViewInternal) _delegateWantsHeaderForSection:]
#2  0x30c8f6f4 in -[UISectionRowData refreshWithSection:tableView:tableViewRowData:]
#3  0x30c90628 in -[UITableViewRowData(UITableViewRowDataPrivate) _ensureSectionOffsetIsValidForSection:]
#4  0x30c8f5d0 in -[UITableViewRowData rectForFooterInSection:]
#5  0x30c3d430 in -[UITableViewRowData heightForTable]
#6  0x30c05430 in -[UITableView(_UITableViewPrivate) _updateContentSize]
#7  0x30c3ce0c in -[UITableView noteNumberOfRowsChanged]
#8  0x30c3c7c0 in -[UITableView reloadData]
#9  0x30e50e60 in -[UITableViewController viewWillAppear:]
#10 0x30c78810 in -[UINavigationController _startTransition:fromViewController:toViewController:]
#11 0x30c783b0 in -[UINavigationController _startDeferredTransitionIfNeeded]
#12 0x30c782a0 in -[UINavigationController viewWillLayoutSubviews]
#13 0x30c5c874 in -[UILayoutContainerView layoutSubviews]
#14 0x30c382d8 in -[UIView(CALayerDelegate) _layoutSublayersOfLayer:]
#15 0x33e871c0 in -[CALayer layoutSublayers]
#16 0x33e86edc in CALayerLayoutIfNeeded
#17 0x33e86844 in CA::Context::commit_transaction
#18 0x33e86474 in CA::Transaction::commit
#19 0x33e8e5dc in CA::Transaction::observer_callback
#20 0x32d5c830 in __CFRunLoopDoObservers
#21 0x32da4346 in CFRunLoopRunSpecific
#22 0x32da3c1e in CFRunLoopRunInMode
#23 0x31bb9374 in GSEventRunModal
#24 0x30bf3c30 in -[UIApplication _run]
#25 0x30bf2230 in UIApplicationMain
#26 0x00002260 in main at main.m:14

```

**3rd call:**

```
#0  0x000086cc in -[RootViewController tableView:viewForHeaderInSection:] at RootViewController.m:444
#1  0x30c901a8 in -[UITableView(UITableViewInternal) _delegateWantsHeaderForSection:]
#2  0x30c3eebc in -[UITableView(_UITableViewPrivate) _updateVisibleHeadersAndFootersNow]
#3  0x30c3e578 in -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow]
#4  0x30c3c514 in -[UITableView layoutSubviews]
#5  0x30c382d8 in -[UIView(CALayerDelegate) _layoutSublayersOfLayer:]
#6  0x33e871c0 in -[CALayer layoutSublayers]
#7  0x33e86edc in CALayerLayoutIfNeeded
#8  0x33e86844 in CA::Context::commit_transaction
#9  0x33e86474 in CA::Transaction::commit
#10 0x33e8e5dc in CA::Transaction::observer_callback
#11 0x32d5c830 in __CFRunLoopDoObservers
#12 0x32da4346 in CFRunLoopRunSpecific
#13 0x32da3c1e in CFRunLoopRunInMode
#14 0x31bb9374 in GSEventRunModal
#15 0x30bf3c30 in -[UIApplication _run]
#16 0x30bf2230 in UIApplicationMain
#17 0x00002260 in main at main.m:14

```

**4th call:**

```
#0  0x000086cc in -[RootViewController tableView:viewForHeaderInSection:] at RootViewController.m:444
#1  0x30c9712c in -[UITableView(UITableViewInternal) _sectionHeaderViewWithFrame:forSection:opaque:reuseViewIfPossible:]
#2  0x30c3f0b4 in -[UITableView(_UITableViewPrivate) _updateVisibleHeadersAndFootersNow]
#3  0x30c3e578 in -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow]
#4  0x30c3c514 in -[UITableView layoutSubviews]
#5  0x30c382d8 in -[UIView(CALayerDelegate) _layoutSublayersOfLayer:]
#6  0x33e871c0 in -[CALayer layoutSublayers]
#7  0x33e86edc in CALayerLayoutIfNeeded
#8  0x33e86844 in CA::Context::commit_transaction
#9  0x33e86474 in CA::Transaction::commit
#10 0x33e8e5dc in CA::Transaction::observer_callback
#11 0x32d5c830 in __CFRunLoopDoObservers
#12 0x32da4346 in CFRunLoopRunSpecific
#13 0x32da3c1e in CFRunLoopRunInMode
#14 0x31bb9374 in GSEventRunModal
#15 0x30bf3c30 in -[UIApplication _run]
#16 0x30bf2230 in UIApplicationMain
#17 0x00002260 in main at main.m:14

```

**5th call:**

```
#0  0x000086cc in -[RootViewController tableView:viewForHeaderInSection:] at RootViewController.m:444
#1  0x30c901a8 in -[UITableView(UITableViewInternal) _delegateWantsHeaderForSection:]
#2  0x30c3eebc in -[UITableView(_UITableViewPrivate) _updateVisibleHeadersAndFootersNow]
#3  0x30c3e578 in -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow]
#4  0x30c3c514 in -[UITableView layoutSubviews]
#5  0x30c382d8 in -[UIView(CALayerDelegate) _layoutSublayersOfLayer:]
#6  0x33e871c0 in -[CALayer layoutSublayers]
#7  0x33e86edc in CALayerLayoutIfNeeded
#8  0x33e86844 in CA::Context::commit_transaction
#9  0x33e86474 in CA::Transaction::commit
#10 0x33e8e5dc in CA::Transaction::observer_callback
#11 0x32d5c830 in __CFRunLoopDoObservers
#12 0x32da4346 in CFRunLoopRunSpecific
#13 0x32da3c1e in CFRunLoopRunInMode
#14 0x31bb9374 in GSEventRunModal
#15 0x30bf3c30 in -[UIApplication _run]
#16 0x30bf2230 in UIApplicationMain
#17 0x00002260 in main at main.m:14

```

**6th call:**

```
#0  0x000086cc in -[RootViewController tableView:viewForHeaderInSection:] at RootViewController.m:444
#1  0x30c9712c in -[UITableView(UITableViewInternal) _sectionHeaderViewWithFrame:forSection:opaque:reuseViewIfPossible:]
#2  0x30c3f0b4 in -[UITableView(_UITableViewPrivate) _updateVisibleHeadersAndFootersNow]
#3  0x30c3e578 in -[UITableView(_UITableViewPrivate) _updateVisibleCellsNow]
#4  0x30c3c514 in -[UITableView layoutSubviews]
#5  0x30c382d8 in -[UIView(CALayerDelegate) _layoutSublayersOfLayer:]
#6  0x33e871c0 in -[CALayer layoutSublayers]
#7  0x33e86edc in CALayerLayoutIfNeeded
#8  0x33e86844 in CA::Context::commit_transaction
#9  0x33e86474 in CA::Transaction::commit
#10 0x33e8e5dc in CA::Transaction::observer_callback
#11 0x32d5c830 in __CFRunLoopDoObservers
#12 0x32da4346 in CFRunLoopRunSpecific
#13 0x32da3c1e in CFRunLoopRunInMode
#14 0x31bb9374 in GSEventRunModal
#15 0x30bf3c30 in -[UIApplication _run]
#16 0x30bf2230 in UIApplicationMain
#17 0x00002260 in main at main.m:14

```