Function format_text_array 

pub fn format_text_array(items: &[Option<String>]) -> String

v7.10.9 — render a TEXT[] in PG’s external array form ({a,b,NULL}). Elements containing whitespace, commas, quotes, or braces get double-quoted with \\ / \" escapes. NULL elements use the literal token NULL. Public so the wire layer can produce the canonical text-mode encoding.