aeron-client/src/main/java/io/aeron/logbuffer/LogBufferDescriptor.java
public static void storeDefaultFrameHeader(final UnsafeBuffer metadataBuffer, final DirectBuffer defaultHeader)
    {
        if (defaultHeader.capacity() != HEADER_LENGTH)
        {
            throw new IllegalArgumentException(
                "Default header length not equal to HEADER_LENGTH: length=" + defaultHeader.capacity());
        }

        metadataBuffer.putInt(LOG_DEFAULT_FRAME_HEADER_LENGTH_OFFSET, HEADER_LENGTH);
        metadataBuffer.putBytes(LOG_DEFAULT_FRAME_HEADER_OFFSET, defaultHeader, 0, HEADER_LENGTH);
    }
public static void storeDefaultFrameHeader(final UnsafeBuffer metadataBuffer, final DirectBuffer defaultHeader)
    {
        if (defaultHeader.capacity() != HEADER_LENGTH)
        {
            throw new IllegalArgumentException(
                "Default header length not equal to HEADER_LENGTH: length=" + defaultHeader.capacity());
        }

        metadataBuffer.putInt(LOG_DEFAULT_FRAME_HEADER_LENGTH_OFFSET, HEADER_LENGTH);
        metadataBuffer.putBytes(LOG_DEFAULT_FRAME_HEADER_OFFSET, defaultHeader, 0, HEADER_LENGTH);
    }
Store the default frame header to the log meta data buffer.

@param metadataBuffer into which the default headers should be stored.
@param defaultHeader  to be stored.
@throws IllegalArgumentException if the defaultHeader larger than {@link #LOG_DEFAULT_FRAME_HEADER_MAX_LENGTH}