fixup! fixup! Task names and GraphVizExt improvements

Author: jpsamaroo

Diff for: ext/GraphVizExt.jl

@@ -119,12 +119,17 @@ function Dagger.render_logs(logs::Dict, ::Val{:graphviz}; disconnected=false,
                     tid, obj = result_info::Pair{Int,LoggedMutableObject}
                     objid = obj.objid
                     task_result[tid] = objid
+                    tid_v = get!(tid_to_vertex, tid) do
+                        add_vertex!(g)
+                        tid_to_vertex[tid] = nv(g)
+                        nv(g)
+                    end
                     v = get!(objid_to_vertex, objid) do
                         add_vertex!(g)
                         objid_to_vertex[objid] = nv(g)
                         nv(g)
                     end
-                    add_edge!(g, tid_to_vertex[tid], v)
+                    add_edge!(g, tid_v, v)
                 end
             elseif category == :move && kind == :finish
                 if haskey(logs[w], :taskargs)