Document closing of PortableDataInputStream in binaryFiles

Hi,

I am using Spark 2.2.0(recent version) to read binary files from S3. I use sc.binaryfiles to read the files.

It is working fine until some 100 file read but later it get hangs indefinitely from 5 up to 40 mins like Avro file read issue(it was fixed in the later releases)

I tried setting the fs.s3a.connection.maximum to some maximum values but didn't help.

And finally i ended up using the spark speculation parameter set which is again didnt help much.

One thing Which I observed is that it is not closing the connection after every read of binary files from the S3.

example :- sc.binaryFiles("s3a://test/test123.zip")

Please look into this major issue!