0.4.0

Core

• you can now set tags at the tracer level like in python with tracer.SetMeta(key, value) (#56)

Integrations:
This release introduces four new integrations to generate spans from commonly used libraries. Look under https://godoc.org/github.com/DataDog/dd-trace-go/tracer#pkg-subdirectories for more details.

• database/sql (#59)
• sqlx (#59)
• redigo (#51)
• go-redis (#47)

Bugfixes

• Fix a bug which caused SpanFromContextDefault to panic (#54)

Improvements

• Use of a single global random number generator, helpfull for generating Span IDs and Trace IDs (#54)
• Add an X-Datadog-Trace-Count header to outbound payloads as a hint for pre-sampling (#61)