Add buffer when reading input stream during fixity check

[mikejritter]

JIRA Ticket: https://fedora-repository.atlassian.net/browse/FCREPO-3872

What does this Pull Request do?

• Adds a buffer when reading input streams during fixity check

How should this be tested?

• Ingest a largeish binary
  • If needed one is provided in the ticket
• Call fcr:fixity on the ingested binary
  • e.g. curl -u fedoraAdmin:fedoraAdmin http://localhost:8080/rest/binary-id/fcr:fixity
  • time curl ... can be used to note the amount of time the call takes
• Build + run the changes from this PR
• Rerun the curl call on fcr:fixity and compare the response times

Notes

Buffer size was informed by guava

Interested parties

Tag (@ mention) interested parties or, if unsure, @fcrepo/committers

[demiankatz]

Thanks, @mikejritter, this definitely makes a huge improvement -- in my test environment, fixity on my large file takes 8 seconds instead of 90 seconds now!