public Builder setSharedOperationExecutor(ExecutorService executorService) {
            this.sharedOperationExecutor = executorService;
            return this;
        }
Sets an executor for running operations. If async operations are enabled and no executor is specified
client will create a default executor.
Executor will stay running after {@code Client#close() } is called. It is application responsibility to close
the executor.
@param executorService - executor service for async operations
@return
client-v2/src/main/java/com/clickhouse/client/api/Client.java