-io/File/readAsBytesSync.html">File.readAsBytesSync</a>, and will block on file IO.
Prefer using <a href="dart-io/SecurityContext/setTrustedCertificatesBytes.html">setTrustedCertificatesBytes</a>.</p>
<p>iOS note: On iOS, this call takes only the bytes for a single DER
encoded X509 certificate. It may be called multiple times to add
multiple trusted certificates to the context. A DER encoded certificate
can be obtained from a PEM encoded certificate by using the openssl tool:</p>
<p>  $ openssl x509 -outfor