Function infer 

pub fn infer(samples: &[Doc], root_name: &str) -> Result<Schema, SchemaError>

Infers a record Schema (rooted at root_name) that accepts every sample in samples. Every sample’s root must be an object (a record shape) – an empty samples list, or any sample whose root is a bare scalar, is a SchemaError. Always infers with allow_any: false – see infer_with_report for the allow_any: true variant.