While it might be more proper to refer to a voice state as composing
a stream (i.e., the IVoiceState is a Stream), this property is ported
up most often to actual user entities. It makes more sense to
communicate that the user is streaming, rather than stating that the
user itself is a stream.
This is also more gramatically consistent with the other voice state
properties (e.g., IsMuted). Movement from noun-form to participle-form
remains inline with the past-participle form used on the other
properties.