in src/Message.cs [356:367]
public int GetEstimatedMessageSize()
{
int size = 0;
if (this.Header != null) size += 64;
if (this.DeliveryAnnotations != null) size += 64;
if (this.MessageAnnotations != null) size += 64;
if (this.Properties != null) size += 64;
if (this.ApplicationProperties != null) size += 64;
if (this.BodySection != null) size += GetEstimatedBodySize(this.BodySection) + 8;
if (this.Footer != null) size += 64;
return size;
}