Weights now uses trace_id to pick a choice

[paivagustavo]

What is the current behavior?

Weights generates a random float for every we need to decide which element to pick.

What is the new behavior?

Weights now uses the last digits from trace_id to generate its weight when making a decision. This means that two different decisions that have the same weight, will happen at the same time.

Additionally, errors are propagated to parent spans.

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Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests(make test) for the changes have been added (for bug fixes / features) and pass
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Lint (make lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
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Does this introduce a breaking change?

• Yes
• No

Weights will now always be deterministic within their trace_id. This means that two distinct elements tagSets vs resourceAttrSets will be consistently chose two if they have the same weights.

[carolynblumberg]

💨