The message object

// Message info
type:
channel:
time:

// Sender info
sender:
chain:

// Content
item_hash:
item_content:
item_type:
hash_type:

channel - text	Channel of the message. Ideally, an application would decide and use one channel.
time - float	Time the message was created in seconds.
type - text	Text representing the message object type. Value is one of POST, AGGREGATE or STORE
chain - text	The chain used by the sender's account. Value can be NULS2, ETH, DOT, CSDK, SOL, AVAX
sender - text	Chain address who sent and is signing the Aggregate Message.
hash_type - optional text	Defaults to sha256. This is the only supported value for now.
item_content - JSON string	JSON string representing the content of the message. The structure of the item_content depends on the type of message created. See POST, AGGREGATE or STORE.
item_hash - hash	The hash of the item_content encrypted with SHA256.
item_type - option