This defines standard option and values for the
openFile() builder API for opening a file:
fs.option.openfile.read.policy
A list of the desired read policy, in preferred order.
standard values are
adaptive, default, random, sequential, vector, whole-file
fs.option.openfile.length
How long the file is.
fs.option.openfile.split.start
start of a task's split
fs.option.openfile.split.end
end of a task's split
These can be used by filesystem connectors to optimize their
reading of the source file, including but not limited to
* skipping existence/length probes when opening a file
* choosing a policy for prefetching/caching data
The hadoop shell commands which read files all declare "whole-file"
and "sequential", as appropriate.
Contributed by Steve Loughran.
Change-Id: Ia290f79ea7973ce8713d4f90f1315b24d7a23da1
75950e47e7