Preface xvii Conventions used There are a number of text conventions used throughout this book. Code in text : Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: “So, now we have created our own async runtime that uses Rust's Futures, Waker, Context, and async/ await. ” A block of code is set as follows: pub trait Future { type Output; fn poll(&mut self)-> Poll State<Self::Output>; } When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold: struct Coroutine0 { stack: Stack0, state: State0, } Any command-line input or output is written as follows: $ cargo run Tips or important notes Appear like this. Get in touch Feedback from our readers is always welcome. General feedback : If you have questions about any aspect of this book, email us at customercare@ packtpub. com and mention the book title in the subject of your message. Errata : Although we have taken every care to ensure the accuracy of our content, mistakes do happen. If you have found a mistake in this book, we would be grateful if you would report this to us. Please visit www. packtpub. com/support/errata and fill in the form.