Method with_null

arrow-csv/src/writer.rs:565–568

Set the value to represent null in output

(mut self, null_value: String)

    /// Set the value to represent null in output
    pub fn with_null(mut self, null_value: String) -> Self {
        self.null_value = Some(null_value);
        self
    }

    /// Get the value to represent null in output
    pub fn null(&self) -> &str {