public String toString() {
      return "GetOpImpl(key=" + key + ")";
    }
Does a region get on a server using connections from the given pool to communicate with the
server.

@param pool the pool to use to communicate with the server.
@param region the region to do the get on
@param key the entry key to do the get on
@param callbackArg an optional callback arg to pass to any cache callbacks
@param clientEvent holder for returning version information
@return the entry value found by the get if any
geode-core/src/main/java/org/apache/geode/cache/client/internal/GetOp.java