17     // std::collections::Bound was stabilized in Rust 1.17  in main()
18     // but it was moved to core::ops later in Rust 1.26:  in main()
19     // https://doc.rust-lang.org/core/ops/enum.Bound.html  in main()
27     // core::cmp::Reverse stabilized in Rust 1.19:  in main()
28     // https://doc.rust-lang.org/stable/core/cmp/struct.Reverse.html  in main()
33     // CString::into_boxed_c_str and PathBuf::into_boxed_path stabilized in Rust 1.20:  in main()
34     // https://doc.rust-lang.org/std/ffi/struct.CString.html#method.into_boxed_c_str  in main()
35     // https://doc.rust-lang.org/std/path/struct.PathBuf.html#method.into_boxed_path  in main()
41     // From<Box<T>> for Rc<T> / Arc<T> stabilized in Rust 1.21:  in main()
42     // https://doc.rust-lang.org/std/rc/struct.Rc.html#impl-From<Box<T>>  in main()
43     // https://doc.rust-lang.org/std/sync/struct.Arc.html#impl-From<Box<T>>  in main()
48     // Duration available in core since Rust 1.25:  in main()
49     // https://blog.rust-lang.org/2018/03/29/Rust-1.25.html#library-stabilizations  in main()
54     // 128-bit integers stabilized in Rust 1.26:  in main()
55     // https://blog.rust-lang.org/2018/05/10/Rust-1.26.html  in main()
57     // Disabled on Emscripten targets before Rust 1.40 since  in main()
58     // Emscripten did not support 128-bit integers until Rust 1.40  in main()
59     // (https://github.com/rust-lang/rust/pull/65251)  in main()
64     // Inclusive ranges methods stabilized in Rust 1.27:  in main()
65     // https://github.com/rust-lang/rust/pull/50758  in main()
67     // https://blog.rust-lang.org/2018/06/21/Rust-1.27.html#library-stabilizations  in main()
73     // Non-zero integers stabilized in Rust 1.28:  in main()
74     // https://blog.rust-lang.org/2018/08/02/Rust-1.28.html#library-stabilizations  in main()
79     // Current minimum supported version of serde_derive crate is Rust 1.31.  in main()
85     // stabilized in Rust 1.34:  in main()
86     // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#tryfrom-and-tryinto  in main()
87     // https://blog.rust-lang.org/2019/04/11/Rust-1.34.0.html#library-stabilizations  in main()