`ECDHE_RSA_WITH_AES_128_GCM_SHA256`

is the cipher that corresponds to "TLS 1.2, RSA with ephemeral Elliptic Curve Diffie-Hellman, AES with 128-bit key in GCM mode, AEAD". `RSA_WITH_AES_128_GCM_SHA256`

is very similar, but uses RSA instead of Elliptic Curve Diffie Hellman for key exchange (see the list of supported ciphers).

However, specifying `TlsCipherSuite.All`

should not take longer time to negotiate - the TLS server chooses a single cipher each time and there is no additional overhead. If might be interesting to try connecting with `ECDHE_RSA_WITH_AES_128_GCM_SHA256`

to see whether it takes longer as well (in general, ECDH key exchange should be actually be *faster* that RSA key exchange).