nil response from RestClient causes 'undefined method `code' for nil:NilClass'

[deepanshumarwah]

azure-log-analytics-data-collector/lib/azure/loganalytics/datacollectorapi/client.rb

Lines 58 to 71 in c9a05ca

	res = RestClient.post( uri, body, headers)
	res
	rescue => e
	c = e.response.code.to_i
	if c == 429 || c == 500 || c==503
	if retries < @max_retries
	retries += 1
	sleep(@retry_sleep_period)
	retry
	end
	end
	raise e
	end
	end

res can be nil here, leading to a scenario where the following is logged from the logstash-output-azure_loganalytics plugin when Azure::Loganalytics::Datacollectorapi::Client.is_success(res) is called and is_success attempts to evaluate res.code
from logstash:

[ERROR][logstash.outputs.azureloganalytics][pipeline-common][pipeline_common_output_azure_log_analytics_ingest] Exception occured in posting to DataCollector API as log type ExampleLogType: 'undefined method `code' for nil:NilClass', data=>[{"original_timestamp":"2021-04-15T10:36:21.315Z","event_uuid":"ede25ed2-0d3e-4898-8c5d-3...

There appears to be a related issue logged at rest-client/rest-client#655