- The library is now released under Apache 2.0 license
- Use Set() instead of Add() in HTTPHeadersCarrier is functionally a breaking change (fixes issue [#159](https://github.com/opentracing/opentracing-go/issues/159))
- 'golang.org/x/net/context' is replaced with 'context' from the standard library
#### Conditionally capture a field using `log.Noop`
In some situations, you may want to dynamically decide whether or not
to log a field. For example, you may want to capture additional data,
such as a customer ID, in non-production environments:
```go
funcCustomer(order*Order)log.Field{
ifos.Getenv("ENVIRONMENT")=="dev"{
returnlog.String("customer",order.Customer.ID)
}
returnlog.Noop()
}
```
#### Goroutine-safety
The entire public API is goroutine-safe and does not require external
synchronization.
## API pointers for those implementing a tracing system
Tracing system implementors may be able to reuse or copy-paste-modify the `basictracer` package, found [here](https://github.com/opentracing/basictracer-go). In particular, see `basictracer.New(...)`.
## API compatibility
For the time being, "mild" backwards-incompatible changes may be made without changing the major version number. As OpenTracing and `opentracing-go` mature, backwards compatibility will become more of a priority.
## Tracer test suite
A test suite is available in the [harness](https://godoc.org/github.com/opentracing/opentracing-go/harness) package that can assist Tracer implementors to assert that their Tracer is working correctly.