Use boot-time for sleep

Boot-time: "This library reimplements std::time::Instant to use suspend-aware monotonic time if target system supports it.
Otherwise it uses monotonic time or reexports std::time::Instant."

Will be obsoleted when tokio-rs/tokio#3185 is resolved.

Fixes redlib-org#22

Cargo.toml

@@ -42,6 +42,7 @@ fastrand = "2.0.1"
 log = "0.4.20"
 pretty_env_logger = "0.5.0"
 dotenvy = "0.15.7"
+boot-time = "0.1.2"
 
 [dev-dependencies]
 lipsum = "0.9.0"

src/oauth.rs

@@ -10,6 +10,10 @@ use log::info;
 
 use serde_json::json;
 
+use boot_time; /*"This library reimplements std::time::Instant to use suspend-aware monotonic time if target system supports it.
+Otherwise it uses monotonic time or reexports std::time::Instant."
+See #22. Will be obsoleted when https://github.com/tokio-rs/tokio/issues/3185 is resolved. */
+
 static REDDIT_ANDROID_OAUTH_CLIENT_ID: &str = "ohXpoqrZYub1kg";
 
 static AUTH_ENDPOINT: &str = "https://accounts.reddit.com";