Send interactive WhatsApp Flow forms — collect structured answers in-chat without leaving the conversation. 
await wazapin.messages.sendFlow({
  channel_id: "wzp_ch_123",
  to: "6281234567890",
  flow_id: "flow_123",
  flow_token: "token_123",
  body: "Please complete this form.",
});
The exact payload depends on your WhatsApp Flow configuration. Keep field names in snake_case, matching the API schema.
Use client.api for advanced Flow endpoints that are not wrapped by a dedicated SDK method yet.