Function eval_batch_parallel 

pub fn eval_batch_parallel(
    docs: &[&[u8]],
    xpath: &CompiledXPath,
    max_threads: usize,
) -> Result<Vec<Vec<String>>>

Evaluate a batch of documents with automatic parallelism.

Automatically allocates threads between inter-document (parsing different docs on different threads) and intra-document (splitting large docs across threads) parallelism based on document sizes.

• Large docs (>256KB): get intra-document parallel parsing
• All docs: processed concurrently across available threads
• Bloom + lazy parsing applied automatically for selective queries