Make some things precisely conditional

I think this is quite an inconvenient way to be carrying on.

Maybe we should disable all dead code warnings unless all features are
also enabled, and just let the compiler get rid of unused stuff later.

crates/tor-socksproto/src/msg.rs

@@ -3,8 +3,11 @@
 use crate::{Error, Result};
 
 use caret::caret_int;
+use std::fmt;
 use std::net::IpAddr;
-use std::{fmt, net::Ipv6Addr};
+
+#[cfg(feature = "arbitrary")]
+use std::net::Ipv6Addr;
 
 use tor_error::bad_api_usage;
 
@@ -206,6 +209,7 @@ impl SocksStatus {
         }
     }
     /// Create a status from a SOCKS4 or SOCKS4a reply code.
+    #[cfg(feature = "client-handshake")]
     pub(crate) fn from_socks4_status(status: u8) -> Self {
         match status {
             0x5A => SocksStatus::SUCCEEDED,
@@ -356,6 +360,7 @@ pub struct SocksReply {
 
 impl SocksReply {
     /// Create a new SocksReply.
+    #[cfg(feature = "client-handshake")]
     pub(crate) fn new(status: SocksStatus, addr: SocksAddr, port: u16) -> Self {
         Self { status, addr, port }
     }