Optimization suggested by @arcz

lib/Echidna/Campaign.hs

@@ -156,7 +156,7 @@ runSymWorker callback vm dict workerId initialCorpus name cs = do
     modify' (\ws -> ws { runningThreads = [] })
     lift callback
 
-    mapM_ (\symTx -> void $ callseq vm (txs ++ [symTx])) symTxs
+    mapM_ (\symTx -> void $ callseq vm' [symTx]) symTxs
 
 -- | Run a fuzzing campaign given an initial universe state, some tests, and an
 -- optional dictionary to generate calls with. Return the 'Campaign' state once