Starting support for tags

oxydsp-flowgraph/src/edge.rs

@@ -11,6 +11,7 @@ use crate::stream::StreamConsumer;
 use crate::stream::StreamProducer;
 use crate::stream::StreamReader;
 use crate::stream::StreamWriter;
+use crate::tag::Tag;
 
 #[derive(Default)]
 pub struct Edge
@@ -82,6 +83,7 @@ impl AnonymousStreamConsumer
 pub struct In<T>
 {
     stream: Option<StreamConsumer<T>>,
+    tag_stream: Option<StreamConsumer<Tag>>,
 
     // Will rarely be accessed
     edge: Arc<Mutex<Edge>>,
@@ -90,6 +92,7 @@ pub struct In<T>
 pub struct Out<T>
 {
     stream: Option<StreamProducer<T>>,
+    tag_stream: Option<StreamProducer<Tag>>,
 
     // Will rarely be accessed
     edge: Arc<Mutex<Edge>>,
@@ -101,9 +104,14 @@ pub fn stream<T>() -> (Out<T>, In<T>)
     (
         Out {
             stream: None,
+            tag_stream: None,
             edge: edge.clone(),
         },
-        In { stream: None, edge },
+        In {
+            stream: None,
+            tag_stream: None,
+            edge,
+        },
     )
 }