Index Symbols 1:1 threading 29 A address space 30 application binary interface (ABI) 97 arithmetic logic units (ALUs) 5 Assembly language 102 asymmetric coroutines 39, 40 async/await keywords 154, 155 asynchronous programming versus concurrency 13 asynchronous Rust challenges 265 future 269 async runtime mental model 131-133 AT&T dialect 102 Await 39 B base example current implementation, changing 177 design 173-176http. rs, modifying 180-183 improving 171, 173 main. rs, modifying 177 runtime. rs, modifying 177-179 b-async-await 156-160 bitflags 76, 78 bitmasks 75-78 Boost. Coroutine 112 BSD/mac OS 51 C callback based approaches 37 advantages and drawbacks 37 callee saved 101 calling convention , 57 c-async-await 160-165 challenges, asynchronous Rust 267 async drop 268 ergonomics, versus efficiency and flexibility 266 explicit, versus implicit reactor instantiation 265, 266 traits 267 completion-based event queues 48, 49 completion port 49