slow_interface_cast

```go
package main

import (
	"testing"
)

type Value struct {
	uintValue   uint
	uint64Value uint64
	LT          func(*Value) bool
}

func NewUintValue(v uint) *Value {
	return &Value{
		uintValue: v,
		LT: func(value *Value) bool {
			return v < value.uintValue
		},
	}
}

type InterfaceValue interface {
	LT(InterfaceValue) bool
}

type UintValue uint

func (v UintValue) LT(value InterfaceValue) bool {
	return v < value.(UintValue)
}

func compareStruct(src *Value, dst *Value) bool {
	return src.LT(dst)
}

func compareInterface(src InterfaceValue, dst InterfaceValue) bool {
	return src.LT(dst)
}

func Benchmark_Struct(b *testing.B) {
	b.ResetTimer()
	src := NewUintValue(1)
	dst := NewUintValue(2)
	for n := 0; n < b.N; n += 1 {
		for i := 1; i <= 100; i += 1 {
			compareStruct(src, dst)
		}
	}
}

func Benchmark_Interface(b *testing.B) {
	b.ResetTimer()
	src := UintValue(1)
	dst := UintValue(2)
	for n := 0; n < b.N; n += 1 {
		for i := 1; i <= 100; i += 1 {
			compareInterface(src, dst)
		}
	}
}
```

```
$ go test -bench . -benchmem
goos: darwin
goarch: amd64
Benchmark_Struct-8               5000000               378 ns/op               0 B/op          0 allocs/op
Benchmark_Interface-8             500000              3506 ns/op            1600 B/op        200 allocs/op
PASS
```