conference: some event can not trigger when close android device network

[zhangyihui1]

1: android join room 2: android publish localStream 3: close android wifi

expect : android client want trigger publication.ended , publication.error, remoteStream.ended, onServerDisconect event

actual: android client not trigger : publication.error ,remoteStream.ended

[zhangyihui1]

mcu: Release-v20190905

[zhangyihui1]

1: android join room 2: android publish localStream 3: android subscribe self forward stream 4: close android wifi

expect : android client want trigger publication.ended , publication.error, subscription.ended , subscription.error , remoteStream.ended, onServerDisconect event

actual: android client not trigger : subscription.error ,remoteStream.ended event