runtime: Add non-try APIs of TryGetXValue to Utf8JsonReader that throw.

We already have the following “convert to .NET type” APIs on Utf8JsonReader:

public ref partial struct Utf8JsonReader
{
// These throw InvalidOperationException if there is a token type mismatch
    public string GetStringValue();
    public bool GetBooleanValue();

// These throw InvalidOperationException if there is a token type mismatch (i.e. not JsonTokenType.Number).
    public bool TryGetInt32Value(out int value);
    public bool TryGetInt64Value(out long value);
    public bool TryGetSingleValue(out float value);
    public bool TryGetDoubleValue(out double value);
    public bool TryGetDecimalValue(out decimal value);
}

Add the following:

public ref partial struct Utf8JsonReader
{
// These throw InvalidOperationException if there is a token type mismatch.
// These throw OverflowException if the number value doesn't fit into the .NET primitive.
    public int GetInt32Value();
    public long GetInt64Value();
    public float GetSingleValue();
    public double GetDoubleValue();
    public decimal GetDecimalValue();
}

Questions:

• What should the semantics of these APIs be (particularly the TryGet APIs)? Should we throw on token type mismatch or return false?
• Should we drop the suffix Value from the names?
• Should we rename these to remove the type name from their names (similar to SequenceReader, BinaryPrimitives, Utf8Parser, etc.)? i.e. just overload: GetValue(out X value) and TryGetValue(out X value)
  • We can only do that if they are void returning with an out parameter. If they return the type, then we need the type names within the method name to disambiguate.
• Do we need other numeric overloads like GetInt16, GetUInt64, etc.?

cc @JeremyKuhne, @GrabYourPitchforks, @KrzysztofCwalina, @stephentoub, @terrajobst , @bartonjs