Set values for Nuget.Client EXPERIMENTAL_HTTP_RETRY (#58386)

* DO NOT MERGE:  Changes to try out experimental retry feature introduced in newer Nuget.Client

* Move to 6.0.100-rc.1.21430.12

eng/pipelines/common/variables.yml

@@ -1,4 +1,14 @@
 variables:
+
+# These values enable longer delays, configurable number of retries, and special understanding of TCP hang-up 
+# See https://github.com/NuGet/Home/issues/11027 for details
+- name: NUGET_ENABLE_EXPERIMENTAL_HTTP_RETRY
+  value: true
+- name: NUGET_EXPERIMENTAL_MAX_NETWORK_TRY_COUNT
+  value: 6
+- name: NUGET_EXPERIMENTAL_NETWORK_RETRY_DELAY_MILLISECONDS
+  value: 1000
+
 - name: isOfficialBuild
   value: ${{ and(ne(variables['System.TeamProject'], 'public'), ne(variables['Build.Reason'], 'PullRequest')) }}
 - name: isFullMatrix

global.json

@@ -1,11 +1,11 @@
 {
   "sdk": {
-    "version": "6.0.100-rc.1.21411.28",
+    "version": "6.0.100-rc.1.21430.12",
     "allowPrerelease": true,
     "rollForward": "major"
   },
   "tools": {
-    "dotnet": "6.0.100-rc.1.21411.28"
+    "dotnet": "6.0.100-rc.1.21430.12"
   },
   "native-tools": {
     "cmake": "3.16.4",