core-1.8.0-rc.1

OpenTelemetry

• TracerProviders can now have a sampler configured via the
  OTEL_TRACES_SAMPLER environment variable. The supported values are:
  always_off, always_on, traceidratio, parentbased_always_on,
  parentbased_always_off, and parentbased_traceidratio. The options
  traceidratio and parentbased_traceidratio may have the sampler probability
  configured via the OTEL_TRACES_SAMPLER_ARG environment variable.
  For details see: OpenTelemetry Environment Variable
  Specification.
  (#5448)

OpenTelemetry.Exporter.Prometheus.AspNetCore

• Fix serializing scope_info when buffer overflows
  (#5407)

• Add target_info to Prometheus exporters when using OpenMetrics
  (#5407)

OpenTelemetry.Exporter.Prometheus.HttpListener

• Fix serializing scope_info when buffer overflows
  (#5407)

• Add target_info to Prometheus exporters when using OpenMetrics
  (#5407)

OpenTelemetry.Exporter.Zipkin

• Zipkin tags used for Instrumentation Library changed from otel.library.name and
  otel.library.version to otel.scope.name and otel.scope.version respectively.
  Old versions of attributes are deprecated, but still exported
  for backward compatibility.
  (#5473)