private void checkClientDisconnect(Optional<RpcCall> rpcCall) throws CallerDisconnectedException {
    if (rpcCall.isPresent()) {
      // If a user specifies a too-restrictive or too-slow scanner, the
      // client might time out and disconnect while the server side
      // is still processing the request. We should abort aggressively
      // in that case.
      long afterTime = rpcCall.get().disconnectSince();
      if (afterTime >= 0) {
        throw new CallerDisconnectedException(
          "Aborting on region " + getRegionInfo().getRegionNameAsString() + ", call " + this
            + " after " + afterTime + " ms, since " + "caller disconnected");
      }
    }
  }
Returns True if a filter rules the scanner is over, done.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/RegionScannerImpl.java