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+# Generators and Pin
+
+So the second difficult part that there seems to be a lot of questions about
+is Generators and the `Pin` type.
+
+## Generators
+
+```
+**Relevant for:**
+
+- Understanding how the async/await syntax works
+- Why we need `Pin`
+- Why Rusts async model is extremely efficient
+```
+
+The motivation for `Generators` can be found in [RFC#2033][rfc2033]. It's very
+well written and I can recommend reading through it (it talks as much about
+async/await as it does about generators).
+
+Basically, there were three main options that were discussed when Rust was 
+desiging how the language would handle concurrency:
+
+1. Stackfull coroutines, better known as green threads.
+2. Using combinators.
+3. Stackless coroutines, better known as generators.
+
+
+[rfc2033]: https://github.com/rust-lang/rfcs/blob/master/text/2033-experimental-coroutines.md