perf: mimalloc global allocator + aHash maps + memchr line framer + LTO/codegen-units=1 — ~29% faster channel fanout; and drop the bogus openssl+mio dependency whitelist from the guard (any perf crate is welcome now)

src/extensible.rs

@@ -4,7 +4,7 @@
 //! no manual free, no dangling data.
 
 use std::any::{Any, TypeId};
-use std::collections::HashMap;
+use crate::map::HashMap;
 
 #[derive(Default)]
 pub struct Extensible {