What is corresponding data type to set in UDF parameter to match RecordType

Hello Beam community, 

I want to have an UDF to take a record as input. Per error info as shown below, it indicates that the input is *RecordType*, but ** what should I set in the UDF parameter so that Beam would not complain about the type compatibility? Below is the rull error trace. Thank you very much!

\==\==\==\==error trace\==\==\==\==\===

Exception in thread "main" org.apache.beam.sdk.extensions.sql.impl.ParseException: Unable to parse query select fooudf(pv.header) from kafka.tracking.PageViewEvent as pvException in thread "main" org.apache.beam.sdk.extensions.sql.impl.ParseException: Unable to parse query select fooudf(pv.header) from kafka.tracking.PageViewEvent as pv at org.apache.beam.sdk.extensions.sql.impl.CalciteQueryPlanner.convertToBeamRel(CalciteQueryPlanner.java:165) at org.apache.beam.sdk.extensions.sql.impl.BeamSqlEnv.parseQuery(BeamSqlEnv.java:103) at org.apache.beam.sdk.extensions.sql.SqlTransform.expand(SqlTransform.java:124) at org.apache.beam.sdk.extensions.sql.SqlTransform.expand(SqlTransform.java:82) at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:539) at org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:473) at org.apache.beam.sdk.values.PBegin.apply(PBegin.java:44) at org.apache.beam.sdk.Pipeline.apply(Pipeline.java:169) at com.linkedin.samza.sql.engine.BeamSqlEntry.preparePipeline(BeamSqlEntry.java:52) at com.linkedin.samza.sql.engine.BeamSqlEntry.exec(BeamSqlEntry.java:41) at com.linkedin.samza.sql.engine.BeamSqlUI.main(BeamSqlUI.java:33)Caused by: org.apache.calcite.tools.ValidationException: org.apache.calcite.runtime.CalciteContextException: From line 1, column 8 to line 1, column 24: No match found for function signature fooudf() at org.apache.calcite.prepare.PlannerImpl.validate(PlannerImpl.java:190) at org.apache.beam.sdk.extensions.sql.impl.CalciteQueryPlanner.convertToBeamRel(CalciteQueryPlanner.java:136) ... 10 moreCaused by: org.apache.calcite.runtime.CalciteContextException: From line 1, column 8 to line 1, column 24: No match found for function signature fooudf() at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:463) at org.apache.calcite.sql.SqlUtil.newContextException(SqlUtil.java:787) at org.apache.calcite.sql.SqlUtil.newContextException(SqlUtil.java:772) at org.apache.calcite.sql.validate.SqlValidatorImpl.newValidationError(SqlValidatorImpl.java:4825) at org.apache.calcite.sql.validate.SqlValidatorImpl.handleUnresolvedFunction(SqlValidatorImpl.java:1739) at org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:270) at org.apache.calcite.sql.SqlFunction.deriveType(SqlFunction.java:215) at org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:5584) at org.apache.calcite.sql.validate.SqlValidatorImpl$DeriveTypeVisitor.visit(SqlValidatorImpl.java:5571) at org.apache.calcite.sql.SqlCall.accept(SqlCall.java:138) at org.apache.calcite.sql.validate.SqlValidatorImpl.deriveTypeImpl(SqlValidatorImpl.java:1657) at org.apache.calcite.sql.validate.SqlValidatorImpl.deriveType(SqlValidatorImpl.java:1642) at org.apache.calcite.sql.validate.SqlValidatorImpl.expandSelectItem(SqlValidatorImpl.java:462) at org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelectList(SqlValidatorImpl.java:4089) at org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelect(SqlValidatorImpl.java:3352) at org.apache.calcite.sql.validate.SelectNamespace.validateImpl(SelectNamespace.java:60) at org.apache.calcite.sql.validate.AbstractNamespace.validate(AbstractNamespace.java:84) at org.apache.calcite.sql.validate.SqlValidatorImpl.validateNamespace(SqlValidatorImpl.java:994) at org.apache.calcite.sql.validate.SqlValidatorImpl.validateQuery(SqlValidatorImpl.java:954) at org.apache.calcite.sql.SqlSelect.validate(SqlSelect.java:216) at org.apache.calcite.sql.validate.SqlValidatorImpl.validateScopedExpression(SqlValidatorImpl.java:929) at org.apache.calcite.sql.validate.SqlValidatorImpl.validate(SqlValidatorImpl.java:633) at org.apache.calcite.prepare.PlannerImpl.validate(PlannerImpl.java:188) ... 11 moreCaused by: org.apache.calcite.sql.validate.SqlValidatorException: No match found for function signature fooudf() at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at org.apache.calcite.runtime.Resources$ExInstWithCause.ex(Resources.java:463) at org.apache.calcite.runtime.Resources$ExInst.ex(Resources.java:572) ... 33 more

Imported from Jira [BEAM-8316](https://issues.apache.org/jira/browse/BEAM-8316). Original Jira may contain additional context.
Reported by: yangzhang.