private TelemetryConfiguration SetupTelemetryConfiguration()
        {
            TelemetryConfiguration config = TelemetryConfiguration.CreateDefault();
            if (this.OnSend != null)
            {
                config.TelemetryChannel = new NoOpTelemetryChannel { OnSend = this.OnSend };
            }

            string resolvedInstrumentationKey = this.nameResolver.Resolve("APPINSIGHTS_INSTRUMENTATIONKEY");
            string resolvedConnectionString = this.nameResolver.Resolve("APPLICATIONINSIGHTS_CONNECTION_STRING");

            bool instrumentationKeyProvided = !string.IsNullOrEmpty(resolvedInstrumentationKey);
            bool connectionStringProvided = !string.IsNullOrEmpty(resolvedConnectionString);

            if (instrumentationKeyProvided && connectionStringProvided)
            {
                this.endToEndTraceHelper.ExtensionWarningEvent(...);
            }

            if (!instrumentationKeyProvided && !connectionStringProvided)
            {
                this.endToEndTraceHelper.ExtensionWarningEvent(...);
            }

            if (instrumentationKeyProvided)
            {
                this.endToEndTraceHelper.ExtensionInformationalEvent(...);

#pragma warning disable CS0618 // Type or member is obsolete
                config.InstrumentationKey = resolvedInstrumentationKey;
#pragma warning restore CS0618 // Type or member is obsolete
            }

            if (connectionStringProvided)
            {
                this.endToEndTraceHelper.ExtensionInformationalEvent(...);

                config.ConnectionString = resolvedConnectionString;
            }

            return config;
        }