Custom `jsonRender` that encodes JSON data directly into the response
stream, it uses less memory since it does not buffer the entire JSON
structure before sending it, unlike `c.JSON` in `HTTPReturn`, which
serializes the JSON fully in memory before writing it to the response.
Benchmark testing shows that, using the custom render incurs no
performance loss and reduces memory consumption by nearly 50%.
issue: https://github.com/milvus-io/milvus/issues/37671
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Signed-off-by: bigsheeper <yihao.dai@zilliz.com>
