Add dump option to RouteGetRequest

With dump set to false, we can mimic the behaviour of `ip route get`.

src/route/get.rs

@@ -16,6 +16,7 @@ use crate::{try_rtnl, Error, Handle};
 pub struct RouteGetRequest {
     handle: Handle,
     message: RouteMessage,
+    dump: bool,
 }
 
 /// Internet Protocol (IP) version.
@@ -38,7 +39,11 @@ impl IpVersion {
 
 impl RouteGetRequest {
     pub(crate) fn new(handle: Handle, message: RouteMessage) -> Self {
-        RouteGetRequest { handle, message }
+        RouteGetRequest {
+            handle,
+            message,
+            dump: true,
+        }
     }
 
     pub fn message_mut(&mut self) -> &mut RouteMessage {
@@ -49,11 +54,15 @@ impl RouteGetRequest {
         let RouteGetRequest {
             mut handle,
             message,
+            dump,
         } = self;
 
         let mut req =
             NetlinkMessage::from(RouteNetlinkMessage::GetRoute(message));
-        req.header.flags = NLM_F_REQUEST | NLM_F_DUMP;
+        req.header.flags = NLM_F_REQUEST;
+        if dump {
+            req.header.flags |= NLM_F_DUMP;
+        }
 
         match handle.request(req) {
             Ok(response) => Either::Left(response.map(move |msg| {