{Object} [metadata=undefined] - A publisher_metadata object to send
with each payload.
property
{String} [host='eventgw.twilio.com'] - The host address of the EA
server to publish to.
property
{Object|Function} [defaultPayload] - A default payload to extend
when creating and sending event payloads. Also takes a function that
should return an object representing the default payload. This is
useful for fields that should always be present when they are
available, but are not always available.
{Object} [metadata=undefined] - A publisher_metadata object to send with each payload.
{String} [host='eventgw.twilio.com'] - The host address of the EA server to publish to.
{Object|Function} [defaultPayload] - A default payload to extend when creating and sending event payloads. Also takes a function that should return an object representing the default payload. This is useful for fields that should always be present when they are available, but are not always available.