params: paramsLjson_msg_param (JSON string of the message)
param message_id
message_id: Buffer where the message ID string is stored. The size of the buffer cannot be less than 128 bytes. After the API is called, a message ID string ended with '\0' can be obtained. If no buffer is required, pass in null.
param user_data
user_data: User-defined data. The IM SDK only transfers the user data to the callback function result_cb without processing the data.
conv_id: Conversation ID
conv_typeConversation type，请参考TIMConvType
params: paramsLjson_msg_param (JSON string of the message)
message_id: Buffer where the message ID string is stored. The size of the buffer cannot be less than 128 bytes. After the API is called, a message ID string ended with '\0' can be obtained. If no buffer is required, pass in null.
user_data: User-defined data. The IM SDK only transfers the user data to the callback function result_cb without processing the data.