Function grpcio_sys::grpc_slice_buffer_add_indexed

pub unsafe extern "C" fn grpc_slice_buffer_add_indexed(
    sb: *mut grpc_slice_buffer, 
    slice: grpc_slice
) -> usize

add an element to a slice buffer - takes ownership of the slice and returns the index of the slice. Guarantees that the slice will not be concatenated at the end of another slice (i.e. the data for this slice will begin at the first byte of the slice at the returned index in sb->slices) The implementation MAY decide to concatenate data at the end of a small slice added in this fashion.