# Functions
TsigGenerate fills out the TSIG record attached to the message.
TsigGenerateByAlgorithm fills out the TSIG record attached to the message using a callback to implement the algorithm-specific generation.
TsigVerify verifies the TSIG on a message.
TsigVerifyByAlgorithm verifies the TSIG on a message using a callback to implement the algorithm-specific verification.
# Structs
A Client defines parameters for a DNS client.
A Conn represents a connection to a DNS server.
Error represents a DNS error.
TSIG is the RR the holds the transaction signature of a message.
TsigAlgorithm holds the two callbacks used to generate and verify the transaction signature of a message.