Deprecate TransactionContext functions

[sahidvelji]

Related to #413

go-sdk/openfeature/evaluation_context.go

Lines 60 to 91 in 4b3d6d9

	// WithTransactionContext constructs a TransactionContext.
	//
	// ctx - the context to embed the EvaluationContext in
	// ec - the EvaluationContext to embed into the context
	func WithTransactionContext(ctx context.Context, ec EvaluationContext) context.Context {
	return context.WithValue(ctx, internal.TransactionContext, ec)
	}
	// MergeTransactionContext merges the provided EvaluationContext with the current TransactionContext (if it exists)
	//
	// ctx - the context to pull existing TransactionContext from
	// ec - the EvaluationContext to merge with the existing TransactionContext
	func MergeTransactionContext(ctx context.Context, ec EvaluationContext) context.Context {
	oldTc := TransactionContext(ctx)
	mergedTc := mergeContexts(ec, oldTc)
	return WithTransactionContext(ctx, mergedTc)
	}
	// TransactionContext extracts a EvaluationContext from the current
	// golang.org/x/net/context. if no EvaluationContext exist, it will construct
	// an empty EvaluationContext
	//
	// ctx - the context to pull EvaluationContext from
	func TransactionContext(ctx context.Context) EvaluationContext {
	ec, ok := ctx.Value(internal.TransactionContext).(EvaluationContext)
	if !ok {
	return EvaluationContext{}
	}
	return ec
	}

My proposal is that we deprecate these functions and turn them into package-level variables that are assigned to the new functions.

• WithTransactionContext should be named ContextWithEvaluationContext.
• TransactionContext should be named EvaluationContextFromContext.

See the OTel trace package for good names for these types of functions.
The convention here is TypeNameFromContext and ContextWithTypeName, where TypeName is the name of the type of identifier being stored/retrieved from the context.

Note that MergeTransactionContext will be handled in a separate issue, as it's a bit more involved.