public ResumableResult runResumable(final ConfigSource config) {
        logger.info("Started Embulk v" + EmbulkVersion.VERSION);

        final ExecSessionInternal exec = this.newExecSessionInternal(config.deepCopy().getNestedOrGetEmpty("exec"));
        try {
            final ExecutionResult result;
            try {
                result = this.bulkLoader.run(exec, config);
            } catch (PartialExecutionException partial) {
                return new ResumableResult(partial);
            }
            return new ResumableResult(result);
        } finally {
            try {
                exec.cleanup();
            } catch (final Exception ex) {
                // TODO add this exception to ExecutionResult.getIgnoredExceptions
                // or partial.addSuppressed
                ex.printStackTrace(System.err);
            }
        }
    }
Sets an alternative {@code BulkLoader} instance mainly for testing-purpose.
embulk-core/src/main/java/org/embulk/EmbulkEmbed.java