Regarding Package Symbols

[TimothyMothra]

Problems

• I recently discovered a problem with our SDK symbols unavailable on Microsoft's Symbol Server. @lmolkova helped me verify.

• As part of the larger repo consolidation Consolidating Application Insights Repos #1214, I'm investigating and consolidating our *.props.
  I discovered that half our products were shipping DebugType Full and the other half was shipping DebugType PdbOnly
  For context:
  In 2018 we investigated changing to the DebugType Portable, but Microsoft's Symbol Server wasn't ready for this change.
  In 2019 I tried to onboard to the Nuget Symbol Server, but they require the DebugType Portable.

TODO

• We need to investigate if we can change to Portable now as recommended here: Discussion: Change default DebugType to embedded for .NET Core 3 dotnet/sdk#2679 (comment)
• Need to investigate what happened to Microsoft Symbol Server.
• Need to finish onboarding to Nuget Symbol Server.

Workaround

• Changing all SDKs to use DebugType Full. https://github.com/microsoft/ApplicationInsights-dotnet/pull/1528/files#diff-958413da6065a421fb6ced33222f648d
• Changing all NUPKGs to include symbols. https://github.com/microsoft/ApplicationInsights-dotnet/pull/1523/files#diff-775eb2dabbb1d381756ae13c69421241