Trace, Span, and Context#

A trace represents a single request flowing through a distributed system. It is identified by a 128-bit trace ID. A span represents one unit of work within that trace – an HTTP handler, a database query, a message publish. Each span has a name, start time, duration, status, attributes (key-value pairs), and events (timestamped annotations). Spans form a tree: every span except the root has a parent span ID.