Merge pull request #505 from hxmhlt/metadata_report

common/constant/default.go

common/constant/key.go

config/instance/metedata_report.go

go.mod

go.sum

metadata/definition/definition.go

metadata/definition/definition_test.go

metadata/definition/mock.go

metadata/identifier/service_metadata_identifier.go

metadata/identifier/subscribe_metadata_identifier.go

metadata/identifier/subscribe_metadata_identifier_test.go

metadata/report/delegate/delegate_report.go

metadata/report/delegate/delegate_report_test.go

metadata/report/report.go

metadata/service/exporter/configurable/exporter.go

metadata/service/inmemory/service.go

metadata/service/inmemory/service_test.go

metadata/service/remote/service.go

metadata/service/remote/service_test.go

metadata/service/service.go