Retrofit请求头

public interface ObservedApis {
@GET
Observable get(@Url String url);

@FormUrlEncoded
@POST
Observable<ResponseBody> post(@Url String url, @FieldMap Map<String, String> map);

@DELETE
Observable<ResponseBody> delete(@Url String url);

@PUT
@FormUrlEncoded
Observable<ResponseBody> put(@Url String url, @FieldMap Map<String, String> parmas);

@POST
@Multipart
Observable<ResponseBody> postImage(@Url String url, @Part MultipartBody.Part parts);

}