Function try_append_secret_string 

pub fn try_append_secret_string(
    value: &mut SecretString,
    text: &str,
    maximum_bytes: usize,
) -> Result<(), SecretStringAppendError>

Fallibly appends text to protected storage within a public byte bound.

Growth allocates and fills replacement storage before clearing the old allocation and swapping it out. Appends within existing capacity cannot allocate. The borrowed source is not cleared.