Build me a new, open-source programming language from scratc...

Prompt

Build me a new, open-source programming language from scratch. Let's call it Go. The main goal is to make building software simple, reliable, and efficient. It should feel modern and be easy for developers to pick up, without a lot of complicated syntax or features. A really important aspect is making it super easy to handle lots of tasks at the same time, so it would be great for building fast backend servers and high-performance network tools. It should also come with a comprehensive standard library that has all the essential tools built-in for things like networking, file handling, and data manipulation, so developers have a strong foundation to start with. Make sure to include all the necessary tooling like a compiler, package manager, and testing frameworks. Let's make its mascot a friendly gopher.