Define a new type.
# Macro parameters
| from_json | Implement `ParseFromJSON` trait. Default is `true` | bool | Y |
| from_parameter | Implement `ParseFromParameter` trait. Default is `true` | bool | Y |
| from_multipart | Implement `ParseFromMultipartField` trait. Default is `true` | bool | Y |
| to_json | Implement `ToJSON` trait. Default is `true` | bool | Y |
| to_header | Implement `ToHeader` trait. Default is `true` | bool | Y |
| external_docs | Specify a external resource for extended documentation | string | Y |
| example | Indicates that the type has implemented `Example` trait | bool | Y |
| rename | Rename the type | string | Y |
# Examples
```rust
use poem_openapi::NewType;
#[derive(NewType)]
struct MyString(String);
```