public void copyFrom(FastByteArrayInputStream source, int offset, int count) {
        if (offset + count > source.getCount()) {
            throw new IndexOutOfBoundsException("Trying to copy data past the end of source" + ", source.size="
                    + source.getCount() + ", offset=" + offset + ", count=" + count);
        }
        byte[] srcBuf = source.getBuf();
        write(srcBuf, offset, count);
    }
Copies data from input stream

@param source source stream
@param offset offset in the source
@param count  number of bytes to copy
clickhouse-data/src/main/java/com/clickhouse/data/format/tsv/FastByteArrayOutputStream.java