Retrofit请求头

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

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

@DELETE
Observable delete(@Url String url);

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

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

}