block: add image streaming block job

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block_int.h b/block_int.h
index 3566acb..4f63870 100644
--- a/block_int.h
+++ b/block_int.h
@@ -327,4 +327,7 @@
 void block_job_cancel(BlockJob *job);
 bool block_job_is_cancelled(BlockJob *job);
 
+int stream_start(BlockDriverState *bs, BlockDriverState *base,
+                 BlockDriverCompletionFunc *cb, void *opaque);
+
 #endif /* BLOCK_INT_H */