by carl@stripe.com:
The docs at http://golang.org/pkg/crypto/x509/#CreateCertificateRequest read:
"""
CreateCertificateRequest creates a new certificate based on a template. The following
members of template are used: Subject, Attributes, SignatureAlgorithm, Extension,
DNSNames, EmailAddresses, and IPAddresses. The private key is the private key of the
signer.
"""
The field on CertificateRequest is named "Extensions," not
"Extension"
by carl@stripe.com: