PostgreSQLMessage+BackendKeyData.swift

extension PostgreSQLMessage {
    /// Identifies the message as cancellation key data.
    /// The frontend must save these values if it wishes to be able to issue CancelRequest messages later.
    struct BackendKeyData {
        /// The process ID of this backend.
        var processID: Int32
        
        /// The secret key of this backend.
        var secretKey: Int32
    }
}

// MARK: String

extension PostgreSQLMessage.BackendKeyData: CustomStringConvertible {
    /// See `CustomStringConvertible`.
    var description: String {
        return "processID: \(processID), secretKey: \(secretKey)"
    }
}

// MARK: Parse

extension PostgreSQLMessage.BackendKeyData {
    /// Parses an instance of this message type from a byte buffer.
    static func parse(from buffer: inout ByteBuffer) throws -> PostgreSQLMessage.BackendKeyData {
        guard let processID = buffer.readInteger(as: Int32.self) else {
            throw PostgreSQLError.protocol(reason: "Could not parse process id from backend key data.")
        }
        guard let secretKey = buffer.readInteger(as: Int32.self) else {
            throw PostgreSQLError.protocol(reason: "Could not parse secret key from backend key data.")
        }
        return .init(processID: processID, secretKey: secretKey)
    }
}