On receiving a mutation_fragment or a mutation triggered by a streaming operation, we pass an enum stream_reason to notify the receiver what the streaming is used for. So the receiver can decide further operation, e.g., send view updates, beyond applying the streaming data on disk. Fixes #3276 Message-Id: <f15ebcdee25e87a033dcdd066770114a499881c0.1539498866.git.asias@scylladb.com>