Performance impact of ModelInspector

[brianpos]

While using the legacy validator I noticed this...

firely-net-sdk/src/Hl7.Fhir.Shims.STU3AndUp/Model/ModelInfo.cs

Line 266 in ffb6d67

var inspector = ModelInspector.ForAssembly(typeof(ModelInfo).GetTypeInfo().Assembly);

The ModelInspector here is a static getter, but doesn't have a static backing property so that it can cache the value...
Hence everytime you use any of the other functions in this file, such as IsInstanceTypeFor() it will create a new ModelInspector and re-import all the things.

Example call in my specific case comes from here:
https://github.com/FirelyTeam/Hl7.Fhir.Validation.Legacy/blob/33596cfab783b73ca23b10d27fa68d672b80a125/src/Hl7.Fhir.Validation.Legacy.Shared/Validation/TypeRefValidationExtensions.cs#L50

Don't know if this sort of thing is impacted in the newer validator too.

@ewoutkramer any thoughts?

[brianpos]

For more background on this, the input to the validator here is an ElementNode based resource fabricated using my port of the java FHIR Mapping Language engine with the IStructureDefinitionSummaryProvider interfaces.