Get Block by BlockHeight. If the BlockHeight is outside the range stored in this Node the result is None
Get multiple Blocks by BlockHeight and length. If the query is outside the range stored in the Node the result is an error.
Get multiple blocks by offset into the container (not BlockHeight) and length. Note that this simply iterates the blocks available in the this particular archive node without taking into account the ledger or the remainder of the archive. For example, if the node contains blocks with heights [100, 199] then iter_blocks(0, 1) will return the block with height 100.