BgLogger returns the default global logger.

Event records event in current tracing span.

Eventf records event in current tracing span with format support.

Hex defines a fmt.Stringer for proto.Message.

Logger gets a contextual logger from current context.

SetTag sets tag kv-pair in current tracing span.

CtxLogKey is the key to retrieve logger from context.

TraceEventKey presents the TraceEventKey in span log.