Fix panic fmt warning

Cargo.toml

@@ -19,7 +19,7 @@ include = [
 [features]
 default = []
 # Enables std usage
-std = []
+std = ["error-code/std"]
 # Enables C API wrapper for platform code.
 c_wrapper = ["cc"]
 # Enables usage of tokio 1.0
@@ -28,7 +28,7 @@ tokio1 = ["tokio_1", "nix", "std"]
 stream = ["futures-core"]
 
 [dependencies]
-error-code = "2"
+error-code = "2.2"
 
 [dependencies.futures-core]
 version = "0.3"

README.md

@@ -7,8 +7,6 @@
 
 Timer facilities for Rust's async story
 
-Minimal Rust version: 1.36
-
 ## Accuracy
 
 Regular timers that do not rely on async event loop tend to be on par with user space timers

src/utils.rs

@@ -28,13 +28,10 @@ macro_rules! os_assert {
     })
 }
 
-#[allow(unused)]
-pub(crate) const ZERO_TIME_FAIL: &str = "Zero timeout makes no sense";
-
 #[allow(unused_macros)]
 #[doc(hidden)]
 macro_rules! assert_time {
     ($time:expr) => ({
-        debug_assert!(!($time.as_secs() == 0 && $time.subsec_nanos() == 0), $crate::utils::ZERO_TIME_FAIL);
+        debug_assert!(!($time.as_secs() == 0 && $time.subsec_nanos() == 0), "Zero timeout makes no sense");
     })
 }