public FileServiceBuilder mediaTypeResolver(MediaTypeResolver mediaTypeResolver) {
        this.mediaTypeResolver = requireNonNull(mediaTypeResolver, "mediaTypeResolver");
        return this;
    }
Sets the {@link MediaTypeResolver} that determines a file's {@link MediaType} using its path.
If not set, {@link MediaTypeResolver#ofDefault()} is used by default.
core/src/main/java/com/linecorp/armeria/server/file/FileServiceBuilder.java