Currently the only user of this method is the ProtcolException constructor, when an UnidentifiedSenderMessageContent is present. All other instances of ProtocolException already use the sender's UUID as sender. So it would be good to have this consistent.
Also brings this in line with similar methods, like getSourceIdentifier on SignalServiceEnvelope in the Android app.
Currently the only user of this method is the ProtcolException constructor, when an UnidentifiedSenderMessageContent is present. All other instances of ProtocolException already use the sender's UUID as sender. So it would be good to have this consistent.
Also brings this in line with similar methods, like getSourceIdentifier on SignalServiceEnvelope in the Android app.