Add small example in readme

README.md

@@ -3,3 +3,32 @@
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+
+Marginally less opaque closures.
+
+Specifically, a `MistyClosure` is just comprises an `OpaqueClosure` and an `IRCode`.
+This is useful if you want to look up the `IRCode` used to generate an `OpaqueClosure`.
+
+## Recommended Use
+
+```julia
+# Get the `IRCode` associated to `sin(5.0)`.
+ir = Base.code_ircode_by_type(Tuple{typeof(sin), Float64})[1][1]
+
+# Produce a `MistyClosure` using it. All kwargs are passed to the `OpaqueClosure`
+# constructor.
+mc = MistyClosure(ir; do_compile=true)
+
+# Call it.
+mc(5.0) == sin(5.0)
+```
+
+## Alterative Use
+
+Sometimes you'll already have an `OpaqueClosure` lying around, and not want to produce a new one from an `IRCode` (as this often takes a surprisingly large amount of time).
+If ths is the case, you can simply use the default constructor for `MistyClosure`.
+That is, write
+```julia
+mc = MistyClosure(existing_opaque_closure, ir)
+```
+Of course, it is _your_ responsibility so ensure that `ir` and `existing_opaque_closure` are in agreement.