Initializes a function that can be used to get the public key from a JWKS URI with the signature
required by the verifyJWT function. You can create a client using the getJwksClient function.
Parameters
client: JwksClient
A JwksClient instance
header: JwtHeader
The JWT header
callback: SigningKeyCallback
The callback function that will be called when the public key is ready
Initializes a function that can be used to get the public key from a JWKS URI with the signature required by the
verifyJWTfunction. You can create a client using thegetJwksClientfunction.