src/Codec/EncodingList.php
public function unless(bool $test, $encodings): self
    {
        return $this->when(true !== $test, $encodings);
    }
public function unless(bool $test, $encodings): self
    {
        return $this->when(true !== $test, $encodings);
    }
Push encodings if the truth test does not evaluate to true.

@param bool $test
@param Encoding|string|iterable|\Closure|null $encodings
@return EncodingList