spanKind top-level constant

String const spanKind

Here we define standard names for tags that can be added to Spans by the instrumentation code. The actual tracing systems are not required to retain these as tags in the stored Spans if they have other means of representing the same data. For example, the spanKind='server' can be inferred from a Zipkin span by the presence of ss/sr annotations. Hints at relationship between Spans, e.g. client/server.

Implementation

/// Hints at relationship between [Span]s, e.g. client/server.
const String spanKind = 'span.kind';