channel的size默认的是1吗？怎么修改channel的size？

vmm_channel ：
function new( string name, string inst, intfull = 1, intempty = 0, bitfill_as_bytes = 0);
full specifies the FIFO depth. empty specifies minimum bounds on the FIFO.fill_as_bytes
specifies if FIFO level is based on number of transactions or number of bytes.