Iobuf.Blit_consume_and_fillBlit_consume_and_fill copies between iobufs and advances both src and dst.
val blit : src:([> Core_kernel.read ], seek) t -> dst:([> Core_kernel.write ], seek) t -> len:int -> unitval blito : src:([> Core_kernel.read ], seek) t -> ?src_len:int -> dst:([> Core_kernel.write ], seek) t -> unit -> unitval unsafe_blit : src:([> Core_kernel.read ], seek) t -> dst:([> Core_kernel.write ], seek) t -> len:int -> unitval blit_maximal : src:([> Core_kernel.read ], seek) t -> dst:([> Core_kernel.write ], seek) t -> int