lib/Request.php
public function withoutHeader(string $field): self {
        $lower = \strtolower($field);

        $clone = clone $this;

        unset(
            $clone->headerCaseMap[$lower],
            $clone->headers[$lower]
        );

        return $clone;
    }
public function withoutHeader(string $field): self {
        $lower = \strtolower($field);

        $clone = clone $this;

        unset(
            $clone->headerCaseMap[$lower],
            $clone->headers[$lower]
        );

        return $clone;
    }
public function withoutHeader ( string $ field ) : self { $ lower = \ strtolower ( $ field ) ; $ clone = clone $ this ; unset ( $ clone -> headerCaseMap [ $ lower ] , $ clone -> headers [ $ lower ] ) ; return $ clone ; }
Remove the specified header field from the message.

@param string $field Header name.

@return Request
Remove the specified header field from the message .