Even though we don't support sampling yet, the following already applies:

3. Add capability to record Attributes that can be used for sampling decision during the Span
   creation time.
4. Remove addLink APIs from the Span interface, and allow recording links only during the span
   construction time.

Reference:

• Approval PR: Change status to approved for 0006-sampling RFC. oteps#28
• OTEP text: https://github.com/open-telemetry/oteps/blob/master/text/0006-sampling.md