Function dumps_sphinx_index 

pub fn dumps_sphinx_index(value: &Value) -> Result<String>

Render Search.setIndex(...) as sphinx.search.js_index does: the payload is json.dumps(data, separators=(',', ':'), sort_keys=True), so every object’s keys are sorted and, with the default ensure_ascii, every non-ASCII character is a \uXXXX escape. objtypes and objnames are keyed by int in Sphinx, so their keys sort numerically rather than as the strings JSON makes of them.