Merge pull request #48 from hubertshelley/perf/file_part

perf(multipart): 保存文件方法调整

silent/src/core/form.rs

@@ -119,7 +119,7 @@ impl FilePart {
     }
     /// Save the file to a new location.
     #[inline]
-    pub fn save(&mut self, path: String) -> Result<u64, SilentError> {
+    pub fn save(&self, path: String) -> Result<u64, SilentError> {
         std::fs::copy(self.path(), Path::new(&path)).map_err(|e| SilentError::BusinessError {
             code: StatusCode::INTERNAL_SERVER_ERROR,
             msg: format!("Failed to save file: {}", e),