minor fix

Author: MahdiBM

Sources/PostgresNIO/Connection/PostgresConnection.swift

@@ -463,8 +463,9 @@ extension PostgresConnection {
         self.channel.write(HandlerTask.extendedQuery(context), promise: nil)
 
         do {
-            let rowStream = try await promise.futureResult.get()
-            let rowSequence = rowStream.asyncSequence()
+            let (rowStream, rowSequence) = try await promise.futureResult.map { rowStream in
+                (rowStream, rowStream.asyncSequence())
+            }.get()
             let result = try await consume(rowSequence)
             try await rowStream.drain().get()
             guard let metadata = PostgresQueryMetadata(string: rowStream.commandTag) else {