code: @Override
      public StartChannelResult startChannel(StartChannelRequest request) {
          request = beforeClientExecution(request);
          return executeStartChannel(request);
      }
docs: Starts an existing channel
  
  @param startChannelRequest
  Placeholder documentation for StartChannelRequest
  @return Result of the StartChannel operation returned by the service.
  @throws BadRequestException
  This request was invalid.
  @throws InternalServerErrorException
  Unexpected internal service error.
  @throws ForbiddenException
  You do not have permission to start the channel.
  @throws BadGatewayException
  Bad Gateway Error
  @throws NotFoundException
  The channel you're requesting to start does not exist.
  @throws GatewayTimeoutException
  Gateway Timeout Error
  @throws TooManyRequestsException
  Request limit exceeded on start channel calls to channel service.
  @throws ConflictException
  The channel is unable to start due to an issue with channel resources.
  @sample AWSMediaLive.StartChannel
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/medialive-2017-10-14/StartChannel" target="_top">AWS API
  Documentation</a>