Function stream_common_triples 

pub fn stream_common_triples<F: FnMut(&Triple) -> Result<()>>(
    file_a: &Path,
    file_b: &Path,
    format_a: Option<InputFormat>,
    format_b: Option<InputFormat>,
    on_triple: F,
) -> Result<()>

Stream-iterate the bnode-free common triples of two RDF files.