/// Non-panicking version of `.unwrap_err()` — returns `Err` if the Result is `Ok`.
macro_rules!check_err{($result:expr)=>{match$result{Err(e)=> e,Ok(_)=>{returnErr(zero_mysql::error::Error::LibraryBug(zero_mysql::error::eyre!(concat!("expected Err: `",stringify!($result),"`")),).into());}}};}