Function encode_pv_request_with_options 

pub fn encode_pv_request_with_options(
    fields: &[&str],
    options: &[(&str, &str)],
    is_be: bool,
) -> Vec<u8> 

Build a pvRequest structure with extra record._options key/value pairs.

options is an ordered list of (name, value) pairs (both strings) that are encoded as structure record { structure _options { string name; ... } } alongside the usual field(...) selector. This is the standard PVAccess mechanism for requesting transport options such as pipeline=true,queueSize=N on a monitor.

Empty options is equivalent to encode_pv_request.