Function hash_result_content 

pub fn hash_result_content(content: &Value) -> u64

Hash one answer’s content, whatever shape it arrived in.

Deliberately not a text projection: projecting objects, numbers and nulls to the empty string would make two different structured results compare equal, which manufactures an “identical” repeat out of nothing.

The leading discriminant is why null and the string "null" cannot collide, in a function whose only job is equality.