Correct answer - "Annotations" : Annotations are simple key-value pairs that are indexed for use
with filter expressions. Use annotations to record data that you want to use to group traces in
the console, or when calling the GetTraceSummaries API.
X-Ray indexes up to 50 annotations per trace.
Incorrect Answers -
"Metadata" - Metadata are key-value pairs with values of any type, including objects and lists,
but that are not indexed. Use metadata to record data you want to store in the trace but don't
need to use for searching traces.
"Segments" - The compute resources running your application logic send data about their work as
segments. A segment provides the resource's name, details about the request, and details about
the work done.
"Sampling" - To ensure efficient tracing and provide a representative sample of the requests that
your application serves, the X-Ray SDK applies a sampling algorithm to determine which requests
get traced. By default, the X-Ray SDK records the first request each second, and five percent of
any additional requests.
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