aeron-cluster/src/main/java/io/aeron/cluster/client/AeronCluster.java
public long offer(final DirectBuffer buffer, final int offset, final int length)
    {
        return publication.offer(headerBuffer, 0, INGRESS_HEADER_LENGTH, buffer, offset, length, null);
    }
public long offer(final DirectBuffer buffer, final int offset, final int length)
    {
        return publication.offer(headerBuffer, 0, INGRESS_HEADER_LENGTH, buffer, offset, length, null);
    }
Non-blocking publish of a partial buffer containing a message plus session header to a cluster.
<p>
This version of the method will set the timestamp value in the header to zero.

@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)}.