added state methods for the unmanaged transaction interface

Author: transistive

src/Contracts/UnmanagedTransactionInterface.php

@@ -40,4 +40,19 @@ public function commit(iterable $statements = []): CypherList;
      * Rolls back the transaction.
      */
     public function rollback(): void;
+
+    /**
+     * Returns whether the transaction has been rolled back.
+     */
+    public function isRolledBack(): bool;
+
+    /**
+     * Returns whether the transaction has been committed.
+     */
+    public function isCommitted(): void;
+
+    /**
+     * Returns whether the transaction is safe to use.
+     */
+    public function isFinished(): void;
 }