Feature Request: Support Raw String Option for HTTP Batch Mode

[bpb]

In some use cases, apis require batched data to be submitted as a raw string rather than wrapped in a JSON array.

Currently the only way to send batched raw data strings is to use the single request mode and create a pre aggregated roll up payload as a string before sinking. This operation is a bit obtuse.

flink-http-connector/src/main/java/com/getindata/connectors/http/internal/sink/httpclient/BatchRequestSubmitter.java

Lines 111 to 122 in b95e7fb

	BodyPublisher publisher;
	// By default, Java's BodyPublishers.ofByteArrays(elements) will just put Jsons
	// into the HTTP body without any context.
	// What we do here is we pack every Json/byteArray into Json Array hence '[' and ']'
	// at the end, and we separate every element with comma.
	elements.add(BATCH_START_BYTES);
	for (HttpSinkRequestEntry entry : reqeustBatch) {
	elements.add(entry.element);
	elements.add(BATCH_ELEMENT_DELIM_BYTES);
	}
	elements.set(elements.size() - 1, BATCH_END_BYTES);
	publisher = BodyPublishers.ofByteArrays(elements);

Please consider adding this functionality in the near future.