decodeDirect

        fn decodeDirect(
            in: *Reader,
            remaining: *Limit,
            encoded_symbol_count: usize,
        ) HuffmanTree.DecodeError!HuffmanTree {
            var weights: [256]u4 = undefined;
            const weights_byte_count = (encoded_symbol_count + 1) / 2;
            remaining.* = remaining.subtract(weights_byte_count) orelse return error.EndOfStream;
            for (0..weights_byte_count) |i| {
                const byte = try in.takeByte();
                weights[2 * i] = @as(u4, @intCast(byte >> 4));
                weights[2 * i + 1] = @as(u4, @intCast(byte & 0xF));
            }
            const symbol_count = encoded_symbol_count + 1;
            return build(&weights, symbol_count);
        }