Issue: HdfsFileInputStream does not support Hadoop’s unbuffer mechanism

Issue: HdfsFileInputStream does not support Hadoop’s unbuffer mechanism: a task in LegoFlow-SWE (Harbor dataset). HdfsFileInputStream currently lacks any unbuffer capability. When a client (like Impala’s file handle cache) expects the stream to support unbuffering and attempts to invoke an…

The task

`HdfsFileInputStream` currently lacks any unbuffer capability. When a client (like Impala’s file handle cache) expects the stream to support unbuffering and attempts to invoke an `unbuffer()` method or check for the `"in:unbuffer"` stream capability, the calls fail:

Part of Lego-X/LegoFlow-SWE.