1.I have a need to initiate multiple transactions to the same contract address in the fastest time and get confirmation from the network. Means that multiple transactions are recorded in the same block.
2.By use Web3.py and Infura.io .On the kovan network test was pass.But on Mainnet each transaction initiated at the same time was confirmed on the block separated by 1 block.
3.Gas limit was 1 million，gas price was instant maximum price.
4.Nonce is no question.I get the first transaction nonce through getTransactionCount(), then the second transaction is set by myself (nonce+1) to ensure the correctness of the nonce, and the test is passed on the kovan network.