Some more xxxx_FIXED ops would be nice

[YuriMyakotin]

Currently IO_URING have only 2 i/o operations with fixed buffers - IORING_OP_WRITE_FIXED and IORING_OP_READ_FIXED.

Is there any way to add in future versions new ops - IORING_OP_SEND_FIXED/IORING_OP_RECV_FIXED (same as write/read, but with flags support, especially MSG_WAITALL for receive)?
And, ofc, UDP versions - IORING_OP_SENDTO_FIXED and IORING_OP_RECVFROM_FIXED?

[isilence]

Currently IO_URING have only 2 i/o operations with fixed buffers - IORING_OP_WRITE_FIXED and IORING_OP_READ_FIXED. Is there any way to add in future versions new ops - IORING_OP_SEND_FIXED/IORING_OP_RECV_FIXED (same as write/read, but with flags support, especially MSG_WAITALL for receive)? And, ofc, UDP versions - IORING_OP_SENDTO_FIXED and IORING_OP_RECVFROM_FIXED?

Normal send/recc would have nearly zero performance benefit because of how it internally works. New zerocopy send opcode though supports registered buffers (see SENDRECV iouring flags). I was thinking to add support just for consistency but later and only if it pans out well

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