diff --git a/Cargo.toml b/Cargo.toml
index 131beea..b1bba77 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -8,6 +8,7 @@ license = "MIT"
 repository = "https://github.com/neoeinstein/stats_alloc"
 documentation = "https://docs.rs/stats_alloc/"
 readme = "README.md"
+edition = "2021"
 exclude = [
     ".gitignore",
     ".editorconfig",
@@ -15,11 +16,3 @@ exclude = [
     "rustfmt.toml",
     "tests/**/*",
 ]
-
-[features]
-default = []
-nightly = []
-
-[package.metadata.docs.rs]
-all-features = true
-rustdoc-args = ["--cfg", "doc_cfg"]
diff --git a/README.md b/README.md
index 01292aa..4bb29d0 100644
--- a/README.md
+++ b/README.md
@@ -9,11 +9,11 @@ production loads to monitor for memory leaks.
 ```rust
 extern crate stats_alloc;
 
-use stats_alloc::{StatsAlloc, Region, INSTRUMENTED_SYSTEM};
+use stats_alloc::{StatsAlloc, Region};
 use std::alloc::System;
 
 #[global_allocator]
-static GLOBAL: &StatsAlloc<System> = &INSTRUMENTED_SYSTEM;
+static GLOBAL: StatsAlloc<System> = StatsAlloc::system();
 
 fn example_using_region() {
     let reg = Region::new(&GLOBAL);
@@ -21,19 +21,6 @@ fn example_using_region() {
     println!("Stats at 1: {:#?}", reg.change());
     // Used here to ensure that the value is not
     // dropped before we check the statistics
-    ::std::mem::size_of_val(&x);
+    let _ = std::mem::size_of_val(&x);
 }
-``` 
-
-## Custom allocators
-
-Currenty wrapping a custom allocator requires the use of the nightly compiler
-and compiling with the "nightly" feature due to the soon to stabilize use of
-the unstable `const_fn_trait_bound` and the fact that the internals of the
-instrumenting type are not public. If that's fine with you, a custom allocator
-can be wrapped as follows:
-
-```rust
-#[global_allocator]
-static GLOBAL: StatsAlloc<System> = StatsAlloc::new(MyCustomAllocator::new());
 ```
diff --git a/src/lib.rs b/src/lib.rs
index faa6225..abdfcf8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,3 @@
-//!
 //! An instrumenting middleware for global allocators in Rust, useful in testing
 //! for validating assumptions regarding allocation patterns, and potentially in
 //! production loads to monitor for memory leaks.
@@ -6,13 +5,11 @@
 //! ## Example
 //!
 //! ```
-//! extern crate stats_alloc;
-//!
-//! use stats_alloc::{Region, StatsAlloc, INSTRUMENTED_SYSTEM};
+//! use stats_alloc::{Region, StatsAlloc};
 //! use std::alloc::System;
 //!
 //! #[global_allocator]
-//! static GLOBAL: &StatsAlloc<System> = &INSTRUMENTED_SYSTEM;
+//! static GLOBAL: StatsAlloc<System> = StatsAlloc::system();
 //!
 //! fn main() {
 //!     let reg = Region::new(&GLOBAL);
@@ -89,17 +86,6 @@ pub struct Stats {
     pub bytes_reallocated: isize,
 }
 
-/// An instrumented instance of the system allocator.
-pub static INSTRUMENTED_SYSTEM: StatsAlloc<System> = StatsAlloc {
-    allocations: AtomicUsize::new(0),
-    deallocations: AtomicUsize::new(0),
-    reallocations: AtomicUsize::new(0),
-    bytes_allocated: AtomicUsize::new(0),
-    bytes_deallocated: AtomicUsize::new(0),
-    bytes_reallocated: AtomicIsize::new(0),
-    inner: System,
-};
-
 impl StatsAlloc<System> {
     /// Provides access to an instrumented instance of the system allocator.
     pub const fn system() -> Self {
@@ -118,7 +104,6 @@ impl StatsAlloc<System> {
 impl<T: GlobalAlloc> StatsAlloc<T> {
     /// Provides access to an instrumented instance of the given global
     /// allocator.
-    #[cfg(feature = "nightly")]
     pub const fn new(inner: T) -> Self {
         StatsAlloc {
             allocations: AtomicUsize::new(0),
@@ -131,21 +116,6 @@ impl<T: GlobalAlloc> StatsAlloc<T> {
         }
     }
 
-    /// Provides access to an instrumented instance of the given global
-    /// allocator.
-    #[cfg(not(feature = "nightly"))]
-    pub fn new(inner: T) -> Self {
-        StatsAlloc {
-            allocations: AtomicUsize::new(0),
-            deallocations: AtomicUsize::new(0),
-            reallocations: AtomicUsize::new(0),
-            bytes_allocated: AtomicUsize::new(0),
-            bytes_deallocated: AtomicUsize::new(0),
-            bytes_reallocated: AtomicIsize::new(0),
-            inner,
-        }
-    }
-
     /// Takes a snapshot of the current view of the allocator statistics.
     pub fn stats(&self) -> Stats {
         Stats {
@@ -267,6 +237,7 @@ unsafe impl<T: GlobalAlloc> GlobalAlloc for StatsAlloc<T> {
         self.inner.alloc_zeroed(layout)
     }
 
+    #[allow(clippy::comparison_chain)]
     unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
         self.reallocations.fetch_add(1, Ordering::SeqCst);
         if new_size > layout.size() {
diff --git a/tests/test.rs b/tests/test.rs
deleted file mode 100644
index 30d6c5b..0000000
--- a/tests/test.rs
+++ /dev/null
@@ -1,17 +0,0 @@
-extern crate stats_alloc;
-
-use stats_alloc::{Region, StatsAlloc, INSTRUMENTED_SYSTEM};
-use std::alloc::System;
-
-#[global_allocator]
-static GLOBAL: &StatsAlloc<System> = &INSTRUMENTED_SYSTEM;
-
-#[test]
-fn example_using_region() {
-    let reg = Region::new(&GLOBAL);
-    let x: Vec<u8> = Vec::with_capacity(1_024);
-    println!("Stats at 1: {:#?}", reg.change());
-    // Used here to ensure that the value is not
-    // dropped before we check the statistics
-    ::std::mem::size_of_val(&x);
-}
diff --git a/tests/nightly.rs b/tests/tests.rs
similarity index 81%
rename from tests/nightly.rs
rename to tests/tests.rs
index 5c480d1..aa36096 100644
--- a/tests/nightly.rs
+++ b/tests/tests.rs
@@ -1,7 +1,3 @@
-#![cfg(feature = "nightly")]
-
-extern crate stats_alloc;
-
 use stats_alloc::{Region, StatsAlloc};
 use std::alloc::System;
 
@@ -15,5 +11,5 @@ fn example_using_region() {
     println!("Stats at 1: {:#?}", reg.change());
     // Used here to ensure that the value is not
     // dropped before we check the statistics
-    ::std::mem::size_of_val(&x);
+    let _ = std::mem::size_of_val(&x);
 }