Switch to Rust 2021 edition

Cargo.toml

@@ -10,7 +10,7 @@ documentation = "https://docs.rs/seed"
 readme = "README.md"
 keywords = ["wasm", "webassembly", "frontend", "framework", "web"]
 categories = ["wasm", "web-programming"]
-edition = "2018"
+edition = "2021"
 
 build = "build.rs"
 

examples/e2e_encryption/client/Cargo.toml

@@ -2,7 +2,7 @@
 name = "client"
 version = "0.1.0"
 authors = ["Your Name <email@address.com>"]
-edition = "2018"
+edition = "2021"
 
 [lib]
 crate-type = ["cdylib"]

examples/e2e_encryption/client/src/lib.rs

@@ -8,7 +8,6 @@ use shared::{
     rand_core::OsRng,
     DefaultCipherSuite,
 };
-use std::convert::TryInto;
 
 // ------ ------
 //     Init

examples/e2e_encryption/server/Cargo.toml

@@ -2,7 +2,7 @@
 name = "server"
 version = "0.1.0"
 authors = ["Your Name <email@address.com>"]
-edition = "2018"
+edition = "2021"
 
 [dependencies]
 tokio = { version = "0.2", features = ["full"] }  # sync with the one in `warp`

examples/e2e_encryption/server/src/main.rs

@@ -8,7 +8,6 @@ use shared::{
     rand_core::OsRng,
     DefaultCipherSuite,
 };
-use std::convert::{TryFrom, TryInto};
 use std::sync::Arc;
 use tokio::sync::Mutex;
 use warp::hyper::body::Bytes;

src/app/streams/backoff_stream.rs

@@ -2,7 +2,6 @@ use futures::channel::mpsc;
 use futures::stream::Stream;
 use gloo_timers::callback::Timeout;
 use rand::{rngs::SmallRng, Rng, SeedableRng};
-use std::convert::TryFrom;
 use std::pin::Pin;
 use std::rc::Rc;
 use std::task::{Context, Poll};

src/browser/fetch/header.rs

@@ -1,7 +1,6 @@
 //! HTTP headers
 
 use std::borrow::Cow;
-use std::iter::FromIterator;
 
 // ------ Headers ------
 

src/browser/fetch/request.rs

@@ -7,7 +7,7 @@ use gloo_timers::callback::Timeout;
 use js_sys::Uint8Array;
 use serde::Serialize;
 use serde_wasm_bindgen as swb;
-use std::{borrow::Cow, cell::RefCell, convert::TryFrom, rc::Rc};
+use std::{borrow::Cow, cell::RefCell, rc::Rc};
 use wasm_bindgen::JsValue;
 
 /// Its methods configure the request, and handle the response. Many of them return the original