presto-rcfile/src/main/java/io/prestosql/rcfile/RcFileDecoderUtils.java/RcFileDecoderUtils/writeLengthPrefixedString
class RcFileDecoderUtils:    public static void writeLengthPrefixedString(SliceOutput out, Slice slice)
    {
        writeVInt(out, slice.length());
        out.writeBytes(slice);
    }