I trussed a process, and they are lines as below. And I want to know the definition of kaio, but there is no manual entry for kaio, so whether can I get the definition?

/1:     kaio(AIOWRITE, 259, 0x3805B2A00, 8704, 0x099C9E000755D3C0) = 0
/1:     kaio(AIOWRITE, 259, 0x380CF9200, 14336, 0x099CC0000755D5B8) = 0
/1:     kaio(AIOWRITE, 259, 0x381573600, 8704, 0x099CF8000755D7B0) = 0
/1:     kaio(AIOWRITE, 259, 0x381ACA600, 8192, 0x099D1A000755D9A8) = 0
/1:     kaio(AIOWAIT, 0xFFFFFFFF7FFFD620)               = 4418032576
/1:             timeout: 600.000000 sec
/1:     kaio(AIOWAIT, 0xFFFFFFFF7FFFD620)               = 4418033080
/1:             timeout: 600.000000 sec
/1:     kaio(AIOWAIT, 0xFFFFFFFF7FFFD620)               = 4418033584
/1:             timeout: 600.000000 sec