Fully lock StreamStore in close(::StreamStore)

Author: JamesWrigley

src/stream.jl

@@ -153,9 +153,10 @@ function Base.isopen(store::StreamStore, id::UInt)
 end
 
 function Base.close(store::StreamStore)
-    store.open || return
-    store.open = false
     @lock store.lock begin
+        store.open || return
+
+        store.open = false
         for buffer in values(store.input_buffers)
             close(buffer)
         end