implement for std::net::IpAddr

Summary:
I want to wrap `IpAddr` in a following diff, so I'm implementing `Allocative`
to make that more natural.

Reviewed By: pallotron

Differential Revision: D62303400

fbshipit-source-id: da973460b78ca7b980dc60aca5364aa8f09fce19

Author: vmagro

allocative/src/impls/std.rs

@@ -12,6 +12,7 @@ mod cell;
 mod collections;
 mod function;
 mod mem;
+mod net;
 mod primitive;
 mod sync;
 mod time;

allocative/src/impls/std/net.rs

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under both the MIT license found in the
+ * LICENSE-MIT file in the root directory of this source tree and the Apache
+ * License, Version 2.0 found in the LICENSE-APACHE file in the root directory
+ * of this source tree.
+ */
+
+use std::net::IpAddr;
+use std::net::Ipv4Addr;
+use std::net::Ipv6Addr;
+
+use crate::allocative_trait::Allocative;
+use crate::visitor::Visitor;
+
+impl Allocative for IpAddr {
+    fn visit<'a, 'b: 'a>(&self, visitor: &'a mut Visitor<'b>) {
+        visitor.enter_self_sized::<Self>().exit();
+    }
+}
+
+impl Allocative for Ipv4Addr {
+    fn visit<'a, 'b: 'a>(&self, visitor: &'a mut Visitor<'b>) {
+        visitor.enter_self_sized::<Self>().exit();
+    }
+}
+
+impl Allocative for Ipv6Addr {
+    fn visit<'a, 'b: 'a>(&self, visitor: &'a mut Visitor<'b>) {
+        visitor.enter_self_sized::<Self>().exit();
+    }
+}