src/Signature/SignatureV4.php
private function getHeaderBlacklist()
    {
        return [
            'cache-control'         => true,
            'content-type'          => true,
            'content-length'        => true,
            'expect'                => true,
            'max-forwards'          => true,
            'pragma'                => true,
            'range'                 => true,
            'te'                    => true,
            'if-match'              => true,
            'if-none-match'         => true,
            'if-modified-since'     => true,
            'if-unmodified-since'   => true,
            'if-range'              => true,
            'accept'                => true,
            'authorization'         => true,
            'proxy-authorization'   => true,
            'from'                  => true,
            'referer'               => true,
            'user-agent'            => true,
            'x-amzn-trace-id'       => true,
            'aws-sdk-invocation-id' => true,
            'aws-sdk-retry'         => true,
        ];
    }
private function getHeaderBlacklist()
    {
        return [
            'cache-control'         => true,
            'content-type'          => true,
            'content-length'        => true,
            'expect'                => true,
            'max-forwards'          => true,
            'pragma'                => true,
            'range'                 => true,
            'te'                    => true,
            'if-match'              => true,
            'if-none-match'         => true,
            'if-modified-since'     => true,
            'if-unmodified-since'   => true,
            'if-range'              => true,
            'accept'                => true,
            'authorization'         => true,
            'proxy-authorization'   => true,
            'from'                  => true,
            'referer'               => true,
            'user-agent'            => true,
            'x-amzn-trace-id'       => true,
            'aws-sdk-invocation-id' => true,
            'aws-sdk-retry'         => true,
        ];
    }
private function getHeaderBlacklist ( ) { return [ 'cache-control' => true , 'content-type' => true , 'content-length' => true , 'expect' => true , 'max-forwards' => true , 'pragma' => true , 'range' => true , 'te' => true , 'if-match' => true , 'if-none-match' => true , 'if-modified-since' => true , 'if-unmodified-since' => true , 'if-range' => true , 'accept' => true , 'authorization' => true , 'proxy-authorization' => true , 'from' => true , 'referer' => true , 'user-agent' => true , 'x-amzn-trace-id' => true , 'aws-sdk-invocation-id' => true , 'aws-sdk-retry' => true , ] ; }
The following headers are not signed because signing these headers
would potentially cause a signature mismatch when sending a request
through a proxy or if modified at the HTTP client level.

@return array
The following headers are not signed because signing these headers would potentially cause a signature mismatch when sending a request through a proxy or if modified at the HTTP client level .