goshawk: buffer channel so shutdown works
goshawk: buffer channel so shutdown works

google/certificate-transparency-go,RJPercival/certificate-transparency-go,daviddrysdale/certificate-transparency-go,google/certificate-transparency-go,daviddrysdale/certificate-transparency-go,google/certificate-transparency-go,daviddrysdale/certificate-transparency-go,RJPercival/certificate-transparency-go,RJPercival/certificate-transparency-go