//custom serializer is provided, use it
Serializer ser = _btree.keySerializer;
byte[] previous = null;
byte[] buffer = new byte[1024];
OpenByteArrayOutputStream out2 = new OpenByteArrayOutputStream(buffer);
SerializerOutput out3 = new SerializerOutput(out2);
for (int i = firstUse ; i < _btree._pageSize; i++) {
if(keys[i] == null){
LeadingValueCompressionProvider.writeByteArray(oos, null, previous, 0);
}else{
out2.reset();
ser.serialize(out3,keys[i]);
byte[] b = out2.toByteArray();
LeadingValueCompressionProvider.writeByteArray(oos, b, previous, 0);
previous = b;
}
}