Added

• HTTPSupplier interface in the propagation API to specify methods to retrieve and store a single value for a key to be associated with a carrier. (#467)
• HTTPExtractor interface in the propagation API to extract information from an HTTPSupplier into a context. (#467)
• HTTPInjector interface in the propagation API to inject information into an HTTPSupplier. (#467)
• Config and configuring Option to the propagator API. (#467)
• Propagators interface in the propagation API to contain the set of injectors and extractors for all supported carrier formats. (#467)
• HTTPPropagator interface in the propagation API to inject and extract from an HTTPSupplier. (#467)
• WithInjectors and WithExtractors functions to the propagator API to configure injectors and extractors to use. (#467)
• ExtractHTTP and InjectHTTP functions to apply configured HTTP extractors and injectors to a passed context. (#467)
• Histogram aggregator. (#433)
• DefaultPropagator function and have it return trace.TraceContext as the default context propagator. (#456)
• AlwaysParentSample sampler to the trace API. (#455)
• WithNewRoot option function to the trace API to specify the created span should be considered a root span. (#451)

Changed

• Renamed WithMap to ContextWithMap in the correlation package. (#481)
• Renamed FromContext to MapFromContext in the correlation package. (#481)
• Move correlation context propagation to correlation package. (#479)
• Do not default to putting remote span context into links. (#480)
• Propagators extrac
• Tracer.WithSpan updated to accept StartOptions. (#472)
• Renamed MetricKind to Kind to not stutter in the type usage. (#432)
• Renamed the export package to metric to match directory structure. (#432)
• Rename the api/distributedcontext package to api/correlation. (#444)
• Rename the api/propagators package to api/propagation. (#444)
• Move the propagators from the propagators package into the trace API package. (#444)
• Update Float64Gauge, Int64Gauge, Float64Counter, Int64Counter, Float64Measure, and Int64Measure metric methods to use value receivers instead of pointers. (#462)
• Moved all dependencies of tools package to a tools directory. (#466)

Removed

• Binary propagators. (#467)
• NOOP propagator. (#467)

Fixed

• Upgraded github.com/golangci/golangci-lint from v1.21.0 to v1.23.6 in tools/. (#492)
• Fix a possible nil-dereference crash (#478)
• Correct comments for InstallNewPipeline in the stdout exporter. (#483)
• Correct comments for InstallNewPipeline in the dogstatsd exporter. (#484)
• Correct comments for InstallNewPipeline in the prometheus exporter. (#482)
• Initialize onError based on Config in prometheus exporter. (#486)
• Correct module name in prometheus exporter README. (#475)
• Removed tracer name prefix from span names. (#430)
• Fix aggregator_test.go import package comment. (#431)
• Improved detail in stdout exporter. (#436)
• Fix a dependency issue (generate target should depend on stringer, not lint target) in Makefile. (#442)
• Reorders the Makefile targets within precommit target so we generate files and build the code before doing linting, so we can get much nicer errors about syntax errors from the compiler. (#442)
• Reword function documentation in gRPC plugin. (#446)
• Send the span.kind tag to Jaeger from the jaeger exporter. (#441)
• Fix metadataSupplier in the jaeger exporter to overwrite the header if existing instead of appending to it. (#441)
• Upgraded to Go 1.13 in CI. (#465)
• Correct opentelemetry.io URL in trace SDK documentation. (#464)
• Refactored reference counting logic in SDK determination of stale records. (#468)
• Add call to runtime.Gosched in instrument acquireHandle logic to not block the collector. (#469)

Changes since v0.2.1.1

8ebc7bb Name context functions consistently (#481)
a6b8058 Update tools (#492)
29cd0c0 Fix a possible nil-dereference crash (#478)
6b97bb0 Move correlation context propagation to correlation package (#479)
bfe569d exporter/metric/stdout: fix incorrect code format comments for InstallNewPipeline (#483)
bd74f31 exporter/metric/dogstatsd: fix incorrect code format comments for InstallNewPipeline (#484)
f9a5484 exporter/metric/prometheus: fix incorrect code format comments for InstallNewPipeline (#482)
84d0a2a prometheus exporter initialize on error based on config (#486)
f99337f Do not always put remote span context into links (#480)
cf7a4d9 Refactor propagators (#467)
c397451 exporter/metric/prometheus: fix wrong module in README.md (#475)
f0c70ff Add StartOptions to Tracer.WithSpan() (#472)
0f1771f Add @MrAlias as an approver (#471)
2584c3e Call Gosched if load an unmapped record (#469)
69df67d Refactor metric records logic (#468)
4818358 Move dependencies of tools package to a tools directory (#466)
cab6b28 Fix URL to opentelemetry.io (#464)
5d6654d Use latest version of golang 1.13 in CI (#465)
493e13f Update metric types to not use pointer receivers (#462)
942713a Replace span relationship with a potentially remote parent context (#451)
574463c Allow dropping items from correlations + docs + cleanups (#454)
6051c81 Add AlwaysParentSample sampler (#455)
32489dd make trace.TraceContext as default context propagator (#456)
8fcdf8b Send span.kind to jaeger and overwrite grpc metadata instead of using append (#441)
405a92a Misc fixes from PR 381 (#443)
6b4acf4 Reorganize propagation code (shrink PR 381) (#444)
437d9af Reword some function documentation in grpc plugin (#446)
7200bb9 finish adding krnowak to approvers (#445)
0278559 Some makefile fixes (#442)
20bb650 Improve detail in stdout exporter (#436)
2c460f0 Adds Histogram Aggregator (#433)
dcd0a10 Rename the sdk/export/metric package name (#432)
3a32a19 fix aggregator.go import package (#431)
2d5ba32 Remove Tracer name prefix for Span names (#430)