aeron-cluster/src/main/java/io/aeron/cluster/service/ClientSession.java
public long offer(final DirectBuffer buffer, final int offset, final int length)
    {
        return cluster.offer(id, responsePublication, buffer, offset, length);
    }
public long offer(final DirectBuffer buffer, final int offset, final int length)
    {
        return cluster.offer(id, responsePublication, buffer, offset, length);
    }
Non-blocking publish of a partial buffer containing a message to a cluster.

@param buffer containing message.
@param offset offset in the buffer at which the encoded message begins.
@param length in bytes of the encoded message.
@return the same as {@link Publication#offer(DirectBuffer, int, int)} when in {@link Cluster.Role#LEADER}
otherwise {@link #MOCKED_OFFER}.