avro

AVRO-3190: Error when trying to read 0 bytes at eof (#1314)

* fix error when trying to read 0 bytes at eof

When reading an avro file record for record each time when reading the last record DataFileReader tries to get the next block but (of course) fails. This fixes the issue.

* AVRO-3190: Return quickly on eof

* AVRO-3190: Unit test for EOF.

* AVRO-3190: Fix unit test to demonstrate problem

Co-authored-by: Stephan Hradek <stephan.hradek@eco.de>