BQ Insert to record type successful not data not inserted

I'm trying to insert data into Bigquery following the example at
text with pre-created table as against the given example.
My code is as follows

type tagInfo struct {
	proj_name string `bigquery:"proj_name"`
	Tags      Tags   `bigquery:"tags"`
}
type Tags struct {
	key    string `bigquery:"key"`
	values string `bigquery:"values"`
}
func insertData() error {
	prjName := "prjName"
	datasetID := "DSName"
	tableID := "TName"

	ctx := context.Background()
	client, err := bigquery.NewClient(ctx, prjName)
	if err != nil {
		return fmt.Errorf("Bigquery.NewClient: %w", err)
	}
	defer client.Close()

	item := &tagInfo{
		proj_name: "Devil",
		Tags: Tags{
			key:    "engcontact",
			values: "Meryl Streep",
		},
	}
	fmt.Printf("Item is: %s", item)
	items := []*tagInfo{item}

	table := client.Dataset(datasetID).Table(tableID)
	inserter := table.Inserter()
	err = inserter.Put(ctx, items)

	if err != nil {
		if multiErr, ok := err.(bigquery.PutMultiError); ok {
			for _, putErr := range multiErr {
				fmt.Printf("failed to insert row %d with err: %v \n", putErr.RowIndex, putErr.Error())
				fmt.Println(putErr.Errors)
			}
		}
		return err
	}
	return nil
}

The code runs successfully, but I do not see any records inserted.
Table structure is as follows

Field name Type Mod Key Collation Default Value Policy Tags
proj_name STRING NULLABLE
tags. RECORD NULLABLE
key. STRING NULLABLE
values. STRING NULLABLE

Not sure what/where is it going wrong, if someone can provide a pointer, hugely appreciated.

TIA
Sreekanth

Expecting the records to be inserted successfully in table.

The fields should be exported. These kind of issues are reported too many times:

• JSON: https://stackoverflow.com/questions/26327391/json-marshalstruct-returns
• BSON: https://stackoverflow.com/questions/52006453/inserting-struct-in-mongodb-in-golang
• YAML: https://stackoverflow.com/questions/29544146/go-unmarshaling-yaml-into-struct
• TOML: https://stackoverflow.com/questions/43218484/not-able-to-read-toml-file-using-go-with-burntsushi-library

type tagInfo struct {
	ProjName string `bigquery:"proj_name"`
	Tags     Tags   `bigquery:"tags"`
}
type Tags struct {
	Key    string `bigquery:"key"`
	Values string `bigquery:"values"`
}

See the doc for (*Inserter).Put:

> ...
>
> If src is ValueSaver, then its Save method is called to produce a row for uploading.
>
> If src is a struct or pointer to a struct, then a schema is inferred from it and used to create a StructSaver. The InsertID of the StructSaver will be empty.
>
> ...

And here is the comment for the inferFields func:

// inferFields extracts all exported field types from struct type.
func inferFields(rt reflect.Type) (Schema, error) {