Function pipe_subrequest 

pub async fn pipe_subrequest<F>(
    session: &mut Session,
    subrequest: PreparedSubrequest,
    subrequest_handle: SubrequestHandle,
    task_filter: F,
    input_body: InputBodyType,
) -> Result<PipeSubrequestState, PipeSubrequestError>
where
    F: FnMut(HttpTask) -> Result<Option<HttpTask>>,