1. A distributed messaging system comprising: a message log having one or more processors, system memory and message log components that compose capture protocols to capture messages from message producers; and a cursor having one or more processors, system memory and cursor components that compose delivery protocols to deliver messages to consumers; wherein the messaging system implements a method of configuring an end-to-end message assurance for message transfer from message providers to message consumers with the message log and the cursor and that includes: an act of receiving runtime configuration data indicating a combination of a capture assurance, a transfer assurance, and a delivery assurance that are to provide a desired end-to-end message assurance for a message transfer in the distributed messaging system; an act of formulating a message log component configuration from the runtime configuration data for activating and deactivating message log components to compose the capture assurance and to compose a first portion of the transfer assurance to interoperate with a corresponding second portion of the transfer assurance provided by the cursor components; an act of formulating a cursor component configuration from the runtime configuration data for activating and deactivating the cursor components to compose the delivery assurance and to compose the corresponding second portion of the transfer assurance to interoperate with the first portion of the transfer assurance provided by the message log components; an act of sending the message log component configuration to the message log to instruct the message log to compose the capture assurance and the first portion of transfer assurance; and an act of sending the cursor component configuration to the cursor to instruct the cursor to compose the delivery assurance and the second portion of the transfer assurance.