Migrate tokio-postgres-native-tls to 2018 edition

tokio-postgres-native-tls/Cargo.toml

@@ -2,6 +2,7 @@
 name = "tokio-postgres-native-tls"
 version = "0.1.0"
 authors = ["Steven Fackler <sfackler@gmail.com>"]
+edition = "2018"
 
 [dependencies]
 futures = "0.1"

tokio-postgres-native-tls/src/lib.rs

@@ -1,15 +1,6 @@
-extern crate native_tls;
-extern crate tokio_io;
-extern crate tokio_postgres;
-extern crate tokio_tls;
+#![warn(rust_2018_idioms)]
 
-#[macro_use]
-extern crate futures;
-
-#[cfg(test)]
-extern crate tokio;
-
-use futures::{Async, Future, Poll};
+use futures::{try_ready, Async, Future, Poll};
 use tokio_io::{AsyncRead, AsyncWrite};
 use tokio_postgres::{ChannelBinding, TlsConnect};
 use tokio_tls::{Connect, TlsStream};

tokio-postgres-native-tls/src/test.rs

@@ -4,7 +4,7 @@ use tokio::net::TcpStream;
 use tokio::runtime::current_thread::Runtime;
 use tokio_postgres::{self, PreferTls, RequireTls, TlsMode};
 
-use TlsConnector;
+use crate::TlsConnector;
 
 fn smoke_test<T>(builder: &tokio_postgres::Builder, tls: T)
 where