TODO.md

Enbed user information to segment:

# In configuration phase
use Aws::Xray::Rack, capture_user_data: ->(env) { env['X-User-Id'] }

# Implementation image:
class Rack
  def call(env)
    @app.call(env)
    capture_user_data.call(env)
  end

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aws field. Especially EC2 and ECS field.

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Send in_progress segment.

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precursor_ids.