presto-hive/src/main/java/io/prestosql/plugin/hive/s3/PrestoS3FileSystem.java/PrestoS3FileSystem/getObjectSize
class PrestoS3FileSystem:    private static long getObjectSize(Path path, ObjectMetadata metadata)
            throws IOException
    {
        Map<String, String> userMetadata = metadata.getUserMetadata();
        String length = userMetadata.get(UNENCRYPTED_CONTENT_LENGTH);
        if (userMetadata.containsKey(SERVER_SIDE_ENCRYPTION) && length == null) {
            throw new IOException(format("%s header is not set on an encrypted object: %s", UNENCRYPTED_CONTENT_LENGTH, path));
        }
        return (length != null) ? Long.parseLong(length) : metadata.getContentLength();
    }