change wget and curl to retry functions

images/macos/provision/utils/xamarin-utils.sh

@@ -1,5 +1,7 @@
 #!/bin/bash -e -o pipefail
 
+source ~/utils/utils.sh
+
 # Xamarin can clean their SDKs while updating to newer versions,
 # so we should be able to detect it during image generation
 downloadAndInstallPKG() {
@@ -175,7 +177,7 @@ downloadNUnitConsole() {
     pushd $TMPMOUNT
 
     sudo mkdir -p $NUNIT3_PATH
-    sudo curl -L -o nunit3.zip $NUNIT3_LOCATION
+    sudo download_with_retries $NUNIT3_LOCATION "." "nunit3.zip"
 
     echo "Installing NUnit 3..."
     sudo unzip nunit3.zip -d $NUNIT3_PATH
@@ -191,7 +193,7 @@ installNuget() {
   echo "Installing nuget $NUGET_VERSION for Mono $MONO_VERSION"
   cd ${MONO_VERSIONS_PATH}/${MONO_VERSION}/lib/mono/nuget
   sudo mv nuget.exe nuget_old.exe
-  sudo curl -L -o nuget.exe $NUGET_URL
+  sudo download_with_retries $NUGET_URL "." "nuget.exe"
   sudo chmod a+x nuget.exe
 }