presto-rcfile/src/main/java/io/prestosql/rcfile/FileRcFileDataSource.java/FileRcFileDataSource/readFully
class FileRcFileDataSource:    @Override
    public void readFully(long position, byte[] buffer, int bufferOffset, int bufferLength)
            throws IOException
    {
        long start = System.nanoTime();

        input.seek(position);
        input.readFully(buffer, bufferOffset, bufferLength);

        readTimeNanos += System.nanoTime() - start;
        readBytes += bufferLength;
    }