Crash Stack (potentially date/calendar related)

Thank you for building this library. We use it and have seen this crash stack. We aren't sure what's causing it but can provide feedback on how it might have happened. Thanks!

com.apple.main-thread
0  libicucore.A.dylib             0x186a64830 icu::UnicodeString::releaseArray() + 48
1  libicucore.A.dylib             0x186a647a8 icu::UnicodeString::~UnicodeString() + 36
2  libicucore.A.dylib             0x186ade840 icu::DateFormatSymbols::dispose() + 264
3  libicucore.A.dylib             0x186adee04 icu::DateFormatSymbols::~DateFormatSymbols() + 36
4  libicucore.A.dylib             0x186adee38 icu::DateFormatSymbols::~DateFormatSymbols() + 12
5  libicucore.A.dylib             0x186b509b8 icu::SimpleDateFormat::adoptCalendar(icu::Calendar*) + 168
6  CoreFoundation                 0x1878d8a34 __cficu_udat_setCalendar + 28
7  CoreFoundation                 0x1878789cc __ResetUDateFormat + 2056
8  CoreFoundation                 0x187877fa0 __SetUpCFDateFormatter + 372
9  Foundation                     0x18833d5e0 -[NSDateFormatter _regenerateFormatter] + 284
10 Foundation                     0x1882fe9b8 -[NSDateFormatter stringForObjectValue:] + 152
11 ASX                        0x1000afe74 +[RCTAppleHealthKit(Utils) buildISO8601StringFromDate:] + 4295556724
12 ASX                        0x1000adb04 __99-[RCTAppleHealthKit(Queries) fetchQuantitySamplesOfType:unit:predicate:ascending:limit:completion:]_block_invoke_2 + 4295547652
13 libdispatch.dylib              0x1867761fc _dispatch_call_block_and_release + 24
14 libdispatch.dylib              0x1867761bc _dispatch_client_callout + 16
15 libdispatch.dylib              0x18677ad68 _dispatch_main_queue_callback_4CF + 1000
16 CoreFoundation                 0x18789a810 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 12
17 CoreFoundation                 0x1878983fc __CFRunLoopRun + 1660
18 CoreFoundation                 0x1877c62b8 CFRunLoopRunSpecific + 444
19 GraphicsServices               0x18927a198 GSEventRunModal + 180
20 UIKit                          0x18d80d7fc -[UIApplication _run] + 684
21 UIKit                          0x18d808534 UIApplicationMain + 208
22 ASX                        0x10004420c main (main.m:16)
23 libdispatch.dylib              0x1867a95b8 (Missing)

GregWilson / react-native-apple-healthkit

Crash Stack (potentially date/calendar related) #25