Does the hearsay rule apply to former testimony of an unavailable witness?

Notwithstanding the hearsay rule, the former testimony of an unavailable witness is admissible under certain circumstances. (Evid. Code, 1291.) A witness is unavailable if, among other things, the witness is "[a]bsent from the hearing and the proponent of his or her statement has exercised reasonable diligence but has been unable to procure his or her attendance by the court's process." (Id., 240, subd. (a)(5).) " 'The proponent of the evidence has the burden of showing by competent evidence that the witness is unavailable.' " (People v. Foy (2016) 245 Cal.App.4th 328, 339 (Foy).)