E/AndroidRuntime( 3977): java.util.ConcurrentModificationException
E/AndroidRuntime( 3977):    at java.util.HashMap$HashIterator.nextEntry(HashMap.java:792)
E/AndroidRuntime( 3977):    at java.util.HashMap$EntryIterator.next(HashMap.java:829)
E/AndroidRuntime( 3977):    at java.util.HashMap$EntryIterator.next(HashMap.java:827)
E/AndroidRuntime( 3977):    at org.json.JSONObject.writeTo(JSONObject.java:666)
E/AndroidRuntime( 3977):    at org.json.JSONStringer.value(JSONStringer.java:237)
E/AndroidRuntime( 3977):    at org.json.JSONArray.writeTo(JSONArray.java:572)
E/AndroidRuntime( 3977):    at org.json.JSONStringer.value(JSONStringer.java:233)
E/AndroidRuntime( 3977):    at org.json.JSONObject.writeTo(JSONObject.java:667)
E/AndroidRuntime( 3977):    at org.json.JSONObject.toString(JSONObject.java:636)
E/AndroidRuntime( 3977):    at com.simperium.android.PersistentStore$DataStore.save(PersistentStore.java:89)
E/AndroidRuntime( 3977):    at com.simperium.client.Bucket$1.run(Bucket.java:195)
E/AndroidRuntime( 3977):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
E/AndroidRuntime( 3977):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
E/AndroidRuntime( 3977):    at java.lang.Thread.run(Thread.java:856)