我的应用程序需要通过电子邮件支持用户反馈。我们更喜欢使用 MFMailComposeViewController 而不是 url 模式，因为我们需要在邮件中附加一些日志文件。但是，当用户按照以下步骤操作时，应用程序可能会因“未能及时恢复”而崩溃。
1. Get into message editing view;
2. "Cancel-->Save Draft";
3. When saving draft, presh home button. Application will enter background state;
4. User launch application again, application will block in launch image. After few second, application will crash.
设备日志说：
Jul 2 15:38:58 unknown SpringBoard[57] <Warning>: com.XXX failed to resume in time
Jul 2 15:38:58 unknown SpringBoard[57] <Warning>: Forcing crash report of XXX[461]...
Jul 2 15:38:59 unknown SpringBoard[57] <Warning>: Finished crash reporting.
Jul 2 15:38:59 unknown com.apple.launchd[1] <Notice>: (UIKitApplication:com.XXX[0x8c58]) Exited: Killed: 9
问题：为什么我的申请在简历期间被阻止？
为什么 MFMailComposeViewController 使用这么长时间来保存草稿？
我怎样才能四处走动以避免撞车？
崩溃报告：
Date/Time: 2012-07-03 09:25:40.222 +0800
OS Version: iPhone OS 5.0.1 (9A405)
Report Version: 104
Exception Type: 00000020
Exception Codes: 0x8badf00d
Highlighted Thread: 0
Application Specific Information:
com.XXX failed to resume in time
Elapsed total CPU time (seconds): 1.720 (user 1.720, system 0.000), 17% CPU
Elapsed application CPU time (seconds): 0.009, 0% CPU
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0:
0 libsystem_kernel.dylib 0x35ca8010 0x35ca7000 + 4112
1 libsystem_kernel.dylib 0x35ca8206 0x35ca7000 + 4614
2 AppSupport 0x376c68c4 0x376b4000 + 75972
3 AppSupport 0x376c52f0 0x376b4000 + 70384
4 AppSupport 0x376c59a6 0x376b4000 + 72102
5 AppSupport 0x376c3cfc 0x376b4000 + 64764
6 AppSupport 0x376c3b8a 0x376b4000 + 64394
7 MessageUI 0x305dea90 0x305d5000 + 39568
8 MessageUI 0x306048b2 0x305d5000 + 194738
9 MessageUI 0x305f3914 0x305d5000 + 125204
10 MessageUI 0x305f2fa0 0x305d5000 + 122784
11 MessageUI 0x306025ce 0x305d5000 + 185806
12 UIKit 0x3727fcd4 0x37143000 + 1297620
13 CoreFoundation 0x33cf742e 0x33ce4000 + 78894
14 UIKit 0x371619e4 0x37143000 + 125412
15 UIKit 0x371619a0 0x37143000 + 125344
16 UIKit 0x3716197e 0x37143000 + 125310
17 UIKit 0x371616ee 0x37143000 + 124654
18 UIKit 0x37162026 0x37143000 + 127014
19 UIKit 0x37160508 0x37143000 + 120072
20 UIKit 0x3715fefa 0x37143000 + 118522
21 UIKit 0x371464e6 0x37143000 + 13542
22 UIKit 0x37145d26 0x37143000 + 11558
23 GraphicsServices 0x30578dec 0x30574000 + 19948
24 CoreFoundation 0x33d7154c 0x33ce4000 + 578892
25 CoreFoundation 0x33d714ee 0x33ce4000 + 578798
26 CoreFoundation 0x33d7033c 0x33ce4000 + 574268
27 CoreFoundation 0x33cf34d6 0x33ce4000 + 62678
28 CoreFoundation 0x33cf339e 0x33ce4000 + 62366
29 GraphicsServices 0x30577fc6 0x30574000 + 16326
30 UIKit 0x3717473c 0x37143000 + 202556
31 XXX 0x00002d26 0x1000 + 7462
32 XXX 0x00002ce4 0x1000 + 7396