pub fn map_key_begin(&mut self) -> Result<&mut Self, crate::Error> {
        self.inner().map_key()?;

        Ok(self)
    }
/**
    Begin a map key.

    The map key must be followed by an item.
    */
Begin a map key.
The map key must be followed by an item.
Begin a map key . The map key must be followed by an item .
pub fn map_key_begin(&mut self) -> Result<&mut Self, crate::Error> {
        self.inner().map_key()?;
        Ok(self)
    }
pub fn map_key_begin ( & mut self ) -> Result < & mut Self , crate :: Error > { self . inner ( ) . map_key ( ) ? ; Ok ( self ) }
Begin a map key.
Begin a map key .
&mut self