stream response to file buffer (#24)

* stream response to file buffer

* Updated changelog

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Changed
+
+- Updated the download method to stream the response into the target file.
+
 ## [v0.4.2](https://github.com/epwalsh/rust-cached-path/releases/tag/v0.4.2) - 2020-09-11
 
 ### Fixed

src/cache.rs

@@ -7,7 +7,6 @@ use reqwest::header::ETAG;
 use std::default::Default;
 use std::env;
 use std::fs::{self, OpenOptions};
-use std::io::Write;
 use std::path::{Path, PathBuf};
 use std::thread;
 use std::time::{self, Duration};
@@ -362,7 +361,7 @@ impl Cache {
     ) -> Result<Meta, Error> {
         debug!("Attempting connection to {}", url);
 
-        let response = self
+        let mut response = self
             .http_client
             .get(url.clone())
             .send()?
@@ -378,7 +377,7 @@ impl Cache {
 
         info!("Starting download of {}", url);
 
-        tempfile_write_handle.write_all(&response.bytes()?)?;
+        response.copy_to(&mut tempfile_write_handle)?;
 
         debug!("Writing meta file");