Evaluates a placeholder expression using the given context.
) -> _PlaceholderResolvedTypeHints
Normally the resolved value will be used as command line flags in strings.
This function does not automatically perform the string conversion, i.e.,
the return type is the same as the type of the value originally has. Currently
it can be
exec property supported primitive types: int, float, string.
if use proto operator: serilaized proto message, or proto primitive fields.
The caller needs to perform desired string conversions.
A placeholder expression to be resolved.
Information needed to resolve the expression.
Resolved expression value.