singlemap
rust singlemap
更新 通过指针转换类型获得引用
```rust
[macro_use]
extern crate singlemap;
[test]
fn testmap(){
singlepush!("a",Box::new("aaaa".tostring()));
let straa = singlegetunwrap!("a",Box).clone();
let refaa = singlegetref!("a");
println!("straa:{:?}",straa);
println!("rustlaa:{:?}",refaa.castref::>());
singlegetreftry!("a",Box,|r:&Box|{
println!("singleget_try:{:?}",r);
},{println!("error")});
}
```