Add an API with the ability to remove a tx from anywhere in the queue…

…; this is handy when the user is notified about a failed tx and doesn't want to stall other txs from executing. Only the user has the context to make that decision, not ATxM.

atxm/machine.py

@@ -521,3 +521,12 @@ def queue_transaction(
             self._wake()
 
         return tx
+
+    def remove_queued_transaction(self, tx: FutureTx):
+        """
+        Removes a queued transaction; useful when an exisitng queued transaction has broadcast
+        failures, or a queued transaction is no longer necessary.
+
+        Returns true if transaction was present and removed, false otherwise.
+        """
+        return self._tx_tracker.remove_queued_tx(tx)

atxm/tracker.py

@@ -257,3 +257,10 @@ def queue_tx(
             f"[tracker] queued transaction #atx-{tx.id} priority {len(self.__queue)}"
         )
         return tx
+
+    def remove_queued_tx(self, tx: FutureTx) -> bool:
+        try:
+            self.__queue.remove(tx)
+            return True
+        except ValueError:
+            return False