Inline various simple `emit_*` and `read_*` methods in `Decoder`.
Inline various simple `emit_*` and `read_*` methods in `Decoder`.

Mostly, these are the ones whose body just contains `f(self)`.

aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust