client.go
func (c *Client) ExportField(field *Field) (io.Reader, error) {
	span := c.tracer.StartSpan("Client.ExportField")
	defer span.Finish()

	var shardsMax map[string]uint64
	var err error

	status, err := c.Status()
	if err != nil {
		return nil, err
	}
	shardsMax, err = c.shardsMax()
	if err != nil {
		return nil, err
	}
	status.indexMaxShard = shardsMax
	shardURIs, err := c.statusToNodeShardsForIndex(status, field.index.Name())
	if err != nil {
		return nil, err
	}

	return newExportReader(c, shardURIs, field), nil
}
func (c *Client) ExportField(field *Field) (io.Reader, error) {
	span := c.tracer.StartSpan("Client.ExportField")
	defer span.Finish()

	var shardsMax map[string]uint64
	var err error

	status, err := c.Status()
	if err != nil {
		return nil, err
	}
	shardsMax, err = c.shardsMax()
	if err != nil {
		return nil, err
	}
	status.indexMaxShard = shardsMax
	shardURIs, err := c.statusToNodeShardsForIndex(status, field.index.Name())
	if err != nil {
		return nil, err
	}

	return newExportReader(c, shardURIs, field), nil
}
// ExportField exports columns for a field.