processId Integer - The internal ID of the renderer process that sent this message
frameId Integer - The ID of the renderer frame that sent this message
returnValue any - Set this to the value to be returned in a synchronous message
senderWebContents - Returns the webContents that sent the message
senderFrameWebFrameMainReadonly - The frame that sent this message
portsMessagePortMain - A list of MessagePorts that were transferred with this message
reply Function - A function that will send an IPC message to the renderer frame that sent the original message that you are currently handling. You should use this method to "reply" to the sent message in order to guarantee the reply will go to the correct process and frame.