fn position(&self, hash: &U256) -> Option<usize> {
        self.0
            .iter()
            .filter(|tx| tx.is_some())
            .position(|tx| &tx.as_ref().unwrap().hash == hash)
    }
/// get tx's position on unconfirmed
get tx's position on unconfirmed
get tx ' s position on unconfirmed
fn position(&self, hash: &U256) -> Option<usize> {
        self.0
            .iter()
            .filter(|tx| tx.is_some())
            .position(|tx| &tx.as_ref().unwrap().hash == hash)
    }
fn position ( & self , hash : & U256 ) -> Option < usize > { self . 0 . iter ( ) . filter ( | tx | tx . is_some ( ) ) . position ( | tx | & tx . as_ref ( ) . unwrap ( ) . hash == hash ) }
get tx's position on unconfirmed
get tx ' s position on unconfirmed
&self
hash
&U256
&self
hash
&U256