title: Can I get useful information from crash information like this?
body: <p>I am using Xamarin.iOS, which is a C# wrapper around Objective-C. This debugging question for C#.</p>
  
  <p>I have a crash that happened in a Task, but that information is not useful, here it is:</p>
  
  <pre><code>*** Terminating app due to uncaught exception 'System.AggregateException', reason: 'System.AggregateException: A Task's exception(s) were not observed either by Waiting on the Task or accessing its Exception property. As a result, the unobserved exception was rethrown by the finalizer thread. ---&gt; Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: &lt;. Path '', line 0, position 0.
    at Newtonsoft.Json.JsonTextReader.ParseValue () &lt;0x100b32280 + 0x004b4&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.JsonTextReader.Read () &lt;0x100b2ed80 + 0x00057&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.JsonReader.ReadAndMoveToContent () &lt;0x100b28ee0 + 0x0001f&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadForType (Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonContract contract, Boolean hasConverter) &lt;0x100b78c70 + 0x00097&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, Boolean checkAdditionalContent) &lt;0x100b6f700 + 0x0008f&gt; in &lt;filename unknown&gt;:0 
    --- End of inner exception stack trace ---
  ---&gt; (Inner Exception #0) Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: &lt;. Path '', line 0, position 0.
    at Newtonsoft.Json.JsonTextReader.ParseValue () &lt;0x100b32280 + 0x004b4&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.JsonTextReader.Read () &lt;0x100b2ed80 + 0x00057&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.JsonReader.ReadAndMoveToContent () &lt;0x100b28ee0 + 0x0001f&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadForType (Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonContract contract, Boolean hasConverter) &lt;0x100b78c70 + 0x00097&gt; in &lt;filename unknown&gt;:0 
    at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, Boolean checkAdditionalContent) &lt;0x100b6f700 + 0x0008f&gt; in &lt;filename unknown&gt;:0 &lt;---
  </code></pre>
  
  <p>From this, I know that somewhere I have a JSON being deserialised that received HTML (starts with <code>&lt;</code>).</p>
  
  <p>Now I was scrolling through the rest of the crash information, and I started thinking about this information:</p>
  
  <pre><code>Thread 1:
  0   libsystem_kernel.dylib               0x000000018ca1c16c 0x18ca1b000 + 4460
  1   CoreFoundation                       0x000000018da17cec 0x18d93b000 + 904428
  2   CoreFoundation                       0x000000018da15908 0x18d93b000 + 895240
  3   CoreFoundation                       0x000000018d944048 0x18d93b000 + 36936
  4   CFNetwork                            0x000000018e135fd0 0x18e067000 + 847824
  5   Foundation                           0x000000018e55347c 0x18e449000 + 1090684
  6   libsystem_pthread.dylib              0x000000018cb00850 0x18cafd000 + 14416
  7   libsystem_pthread.dylib              0x000000018cb00760 0x18cafd000 + 14176
  8   libsystem_pthread.dylib              0x000000018cafddac 0x18cafd000 + 3500
  </code></pre>
  
  <p>What do these numbers signify? And can I retrieve which file or even which method was called from these numbers?</p>