public Optional<byte[]> checkSplit() {
    return checkSplit(false);
  }
Executes a single protocol buffer coprocessor endpoint {@link Service} method using the
registered protocol handlers. {@link Service} implementations must be registered via the
{@link #registerService(Service)} method before they are available.
@param controller an {@code RpcContoller} implementation to pass to the invoked service
@param call       a {@code CoprocessorServiceCall} instance identifying the service, method,
                  and parameters for the method invocation
@return a protocol buffer {@code Message} instance containing the method's result
@throws IOException if no registered service handler is found or an error occurs during the
                    invocation
@see #registerService(Service)
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java