called on an uninitialized AudioRecord.

[githubca]

Got this error when click 'Listen' button:
ApiAiSDK.AIServiceException: startRecording() called on an uninitialized AudioRecord. ---> Java.Lang.IllegalStateException: startRecording() called on an uninitialized AudioRecord.
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in <896ad1d315ca4ba7b117efb8dacaedcf>:0
at Java.Interop.JniEnvironment+InstanceMethods.CallVoidMethod (Java.Interop.JniObjectReference instance, Java.Interop.JniMethodInfo method, Java.Interop.JniArgumentValue* args) [0x00069] in :0 at Java.Interop.JniPeerMembers+JniInstanceMethods.InvokeVirtualVoidMethod (System.String encodedMember, Java.Interop.IJavaPeerable self, Java.Interop.JniArgumentValue* parameters) [0x0002a] in :0
at Android.Media.AudioRecord.StartRecording () [0x0000a] in <9663139ab15947a89e15a6bcd9621f68>:0
at ApiAi.Android.SpeaktoitRecognitionService.StartRecording () [0x0001d] in <686d17a8a1024a75a3fbc81e7e7a6ccd>:0
at ApiAi.Common.BaseSpeaktoitRecognitionService.StartListening () [0x00022] in <686d17a8a1024a75a3fbc81e7e7a6ccd>:0

Any idea why AudioRecord is uninitialized?