disable unwanted dotnet options

tools/internal_ci/helper_scripts/prepare_build_macos_rc

@@ -69,6 +69,11 @@ export PYTHONPATH=/Library/Python/3.4/site-packages
 # set xcode version for Obj-C tests
 sudo xcode-select -switch /Applications/Xcode_9.2.app/Contents/Developer/
 
+# Disable some unwanted dotnet options
+export NUGET_XMLDOC_MODE=skip
+export DOTNET_SKIP_FIRST_TIME_EXPERIENCE=true
+export DOTNET_CLI_TELEMETRY_OPTOUT=true
+
 # TODO(jtattermusch): better debugging of clock skew, remove once not needed
 date
 

tools/internal_ci/helper_scripts/prepare_build_windows.bat

@@ -34,4 +34,9 @@ netsh interface ip add dnsservers "Local Area Connection 8" 8.8.4.4 index=3
 @rem Needed for big_query_utils
 python -m pip install google-api-python-client
 
+@rem Disable some unwanted dotnet options
+set NUGET_XMLDOC_MODE=skip
+set DOTNET_SKIP_FIRST_TIME_EXPERIENCE=true
+set DOTNET_CLI_TELEMETRY_OPTOUT=true
+
 git submodule update --init