fs/io/GzipOutputStream: increase buffer size to 16 kB

src/fs/io/GzipOutputStream.cxx

@@ -62,7 +62,7 @@ GzipOutputStream::Flush()
 	z.avail_in = 0;
 
 	while (true) {
-		Bytef output[4096];
+		Bytef output[16384];
 		z.next_out = output;
 		z.avail_out = sizeof(output);
 
@@ -87,7 +87,7 @@ GzipOutputStream::Write(const void *_data, size_t size)
 	z.avail_in = size;
 
 	while (z.avail_in > 0) {
-		Bytef output[4096];
+		Bytef output[16384];
 		z.next_out = output;
 		z.avail_out = sizeof(output);