fix: Enhance ZstdCompressor with proper binary handling

Signed-off-by: ddukbg <[email protected]>

lib/fluent/plugin/out_s3.rb

@@ -648,14 +648,29 @@ def content_type
 
       def compress(chunk, tmp)
         begin
-          data = chunk.open { |io| io.read }
-          compressed = Zstd.compress(data, level: @level)
-          tmp.write(compressed)
-          tmp.flush
-          tmp.close
+          data = ''
+          chunk.open { |io| data = io.read }
+
+          compressed = nil
+          begin
+            compressed = Zstd.compress(data, level: @level)
+          rescue => e
+            log.warn "Failed to compress with zstd: #{e.message}"
+            raise e
+          end
+
+          if compressed
+            tmp.binmode
+            tmp.write(compressed)
+            tmp.flush
+          else
+            raise "Failed to compress data with zstd"
+          end
         rescue => e
           log.warn "zstd compression failed: #{e.message}"
           raise e
+        ensure
+          tmp.close rescue nil
         end
       end
     end