Merge pull request #10025 from NipunaMadhushan/update-observability-doc

Update New Relic guide

Author: sm1990

swan-lake/development-tutorials/observability/supported-observability-tools-and-platforms/new-relic.md

@@ -40,13 +40,19 @@ metricsEnabled=true
 metricsReporter="newrelic"
 
 [ballerinax.newrelic]
-apiKey="<NEW_RELIC_LICENSE_KEY>"    
-tracingSamplerType="const"          
-tracingSamplerParam=1               
-tracingReporterFlushInterval=15000  
-tracingReporterBufferSize=10000     
-metricReporterFlushInterval=15000   
-metricReporterClientTimeout=10000
+apiKey="<NEW_RELIC_LICENSE_KEY>"    # Mandatory Configuration.
+tracingSamplerType="const"          # Optional Configuration. Default value is 'const'
+tracingSamplerParam=1               # Optional Configuration. Default value is 1
+tracingReporterFlushInterval=15000  # Optional Configuration. Default value is 15000 milliseconds
+tracingReporterBufferSize=10000     # Optional Configuration. Default value is 10000
+metricReporterFlushInterval=15000   # Optional Configuration. Default value is 15000 milliseconds
+metricReporterClientTimeout=10000   # Optional Configuration. Default value is 10000 milliseconds
+isTraceLoggingEnabled=false         # Optional Configuration. Default value is false
+isPayloadLoggingEnabled=false       # Optional Configuration. Default value is false
+
+[ballerinax.newrelic.additionalAttributes]      # Optional Configuration. Add custom attributes (key & value pair) to metrics
+key1 = "<VALUE_1>"
+key2 = "<VALUE_2>"
 ```
 
 >**Tip:** User can configure the environment variable `BALLERINA_NEW_RELIC_API_KEY` instead of apiKey in `Config.toml`. If both are configured, apiKey in `Config.toml` will be overwritten by the environment variable value.