presto-main/src/main/java/io/prestosql/operator/HttpPageBufferClient.java/HttpPageBufferClient/getTaskInstanceId
class HttpPageBufferClient:        private static String getTaskInstanceId(Response response)
        {
            String taskInstanceId = response.getHeader(PRESTO_TASK_INSTANCE_ID);
            if (taskInstanceId == null) {
                throw new PageTransportErrorException(format("Expected %s header", PRESTO_TASK_INSTANCE_ID));
            }
            return taskInstanceId;
        }