void close(Exception exception) {
    forceClose = true;
    onResponseComplete(exception);
  }
Sends a response to the client based on the {@code exception} and marks the channel as closed. The process of
closing the network channel is also initiated.
<p/>
Functionality is the same as {@link #onResponseComplete(Exception)} except that the channel is always closed after
the response sending is complete.
@param exception the {@link Exception} to use while constructing an error message for the client.
ambry-rest/src/main/java/com/github/ambry/rest/NettyResponseChannel.java