The default read-only implementation of Span.
The default read-only implementation of Span. You typically should not need to directly reference this class; instead, use the Span.apply method to construct new instances.
This Proxy trait allows you to extend the Span trait with additional state or behavior and implement the read-only methods from Span using an underlying instance.
Field information in declaration order.
Checks that all required fields are non-null.
A trace is a series of spans (often RPC calls) which form a latency tree.
The root span is where trace_id = id and parent_id = Nil. The root span is usually the longest interval in the trace, starting with a SERVER_RECV annotation and ending with a SERVER_SEND.