Add individual source names to their metadata

src/calng/ShmemToZMQ.py

@@ -55,6 +55,7 @@ class ShmemToZMQ(PipeToZeroMQ.PipeToZeroMQ):
 
             new_meta[source] = conversion.meta_to_dict(metadata)
             new_meta[source]["ignored_keys"] = ignore
+            new_meta[source]["source"] = source
 
             shmem_name, _, _, shmem_index = shmem_utils.parse_shmem_handle(
                 handle_string
@@ -104,6 +105,7 @@ class ShmemToZMQ(PipeToZeroMQ.PipeToZeroMQ):
                     data.get(f"unstacked.{source}"), paths=forward, version=self.version
                 )
                 new_meta[source] = conversion.meta_to_dict(metadata)
+                new_meta[source]["source"] = source
             data.erase("unstacked")
 
         # forward data to all connected ZMQ sockets